How do you translate a MusicXML 4.0 score without accidentally changing what musicians perform? A digital sheet-music file contains more than the words printed above a staff. It represents pitches, rhythmic values, measures, parts, notation, directions, lyrics and playback information that notation software can exchange. MusicXML localization means adapting the text that musicians need to read in another language while keeping the music’s structural and expressive identity intact. If a new-language part label causes a transposition mistake or an edited direction changes performance timing, the result is no longer merely a translation.
People searching for MusicXML translation, MusicXML 4.0 localization, multilingual music notation, score part-name translation, rehearsal-mark translation or digital sheet-music quality assurance need a practical way to distinguish readable text from encoded musical instructions. Terms such as Allegro, piano and C may have different functions in context. A score can include a player-facing instruction, an instrument name, an embedded lyric, a note pitch and a technical identifier in adjacent XML elements. Treating all those strings as ordinary words is an invitation to errors.
This guide explains MusicXML 4.0 as a score-exchange format and shows how to prepare, translate, validate and test language editions of music notation. It is designed for composers, educators, publishers, orchestras, ensemble librarians, music technologists and translators working internationally. Rather than repeating the narrow task of syllable-by-syllable lyric alignment, the focus is the complete score: part relationships, names, directions, transpositions, rehearsal navigation, layout and evidence that the notes remain the same. Translation should help performers use the file, not change the composition.
1. MusicXML is an interchange format, not a word document
MusicXML represents digital musical notation for exchange among applications, editing and archival reuse. It can encode score structure, individual parts, note events, rhythms, dynamics, lyrics, technical directions and layout preferences. A translated file therefore has to work as data and as printed sheet music. Editing a visible word may affect an XML structure that notation software interprets. The first job is to identify text intended for musicians while excluding note pitches, durations, measure links and instrument parameters from translation. Musical meaning is carried partly by notation rather than by ordinary language.
2. Confirm the exact specification and application behavior
MusicXML 4.0 was published as a W3C Music Notation Community Group Final Report in June 2021. The format is widely implemented, but notation applications do not necessarily preserve every element when importing and exporting. Record the source MusicXML version, producing program, receiving applications and whether a compressed MXL package is involved. A valid file may still render differently in another product. Before translation, import the source into the expected tools and document how parts, fonts, repeat endings and rehearsal symbols appear. This baseline separates format limitations from translation defects.
3. Establish which score is authoritative
A composition may exist as a conductor score, instrumental parts, a reduction, a transposed edition and an editable MusicXML export. Choose the approved musical source before changing labels. Record its edition, arranger, publisher, instrumentation and revision date. Do not treat a newly exported file as authoritative merely because it opens cleanly. A late correction to a clarinet part, for example, may exist only in the final rehearsal edition. A translated file must derive from the correct musical snapshot so that textual localization is not blamed for pre-existing note differences or omissions.
4. Classify score data by consequence
Separate translatable human text, established musical terminology, notation symbols, structured numeric values, file references and composition identifiers. A movement title may accept a target-language translation; a MIDI pitch or note duration does not. A printed tempo description may need a reviewed equivalent; the metronome marking and sounding tempo must remain intact. A part name can be translated for readability while its underlying part ID remains stable. Document these distinctions for every type of text extracted. The goal is to protect what a performer hears and plays while improving what a performer reads.
5. Score-partwise and score-timewise organisation
MusicXML supports score-partwise and score-timewise representations. In one, parts organise collections of measures; in the other, measures organise collections of parts. Translation tools must not assume the same document traversal for both. Musical content can be equivalent even though the XML hierarchy is arranged differently. Protect the source representation unless an authorised conversion is required. Extract translatable text using schema-aware paths rather than broad pattern matching. A replacement pass that accidentally changes measure order or loses a part is a structural edit to the score, not a localization step.
6. Part IDs link names to notes
Each score-part entry helps describe a part and connect it with musical material. A name such as Violin, Horn in F or Voice may be localized according to ensemble conventions, but a part identifier must remain unchanged. If the visible label is revised without maintaining its link to the part’s measures, the score may display the wrong stave heading or detach instrument information. Compare the part list before and after translation, including IDs, names, abbreviations and linked instruments. A musician-friendly label succeeds only when it still identifies the exact same line of music.
7. Instrument names carry musical conventions
Instrument names are not always straightforward nouns. English horn, cor anglais, horn in F, bass clarinet and contrabassoon may have established names that vary by music tradition. Some names also encode transposition or register. Use an approved orchestration glossary and the source instrumentation, rather than translating words literally. Preserve the technical instrument assignment and verify that the displayed label describes the same instrument. Do not turn an English horn into a horn because the target-language name looks shorter. Where orchestral libraries require abbreviations, record official short forms and check them in printed part headers.
8. Abbreviated part names are a separate design task
A full part name may fit the first system but not subsequent staves. MusicXML can represent abbreviated labels, which must be understandable yet compact in the target language. Translate them independently with regard to local orchestral convention. An abbreviation that is obvious to one ensemble may resemble another instrument in a different language. Test full score and individual extracted parts, including long movement titles and crowded systems. The notation application’s default handling of abbreviations may differ from the XML source. A successful translation is not merely linguistically accurate; it is scannable during performance.
9. Transposition must be protected
For transposing instruments, written pitch and sounding pitch differ. MusicXML includes explicit transposition information; changing that data to match the translated instrument name would alter musical behavior. Preserve chromatic, diatonic and octave-related transposition settings and verify them in printed and concert-pitch views where available. A clarinet player’s written C should not become a different sounding note because the file was localized. Use a known test passage to compare the source and target. Instrument translation and transposition editing are distinct activities with different authority and validation requirements.
10. Notes encode more than a note name
A note can contain pitch, accidentals, ties, duration, voice, staff and many notation details. These are not words for translation even if their XML element names resemble everyday English. Preserve note count and logical order for each part and measure. A source-to-target comparison should assess pitch events and rests, not just whether the sheet-music page looks similar. A repeated note can hide a changed tie, and a visually similar accidental can affect playback. The safest process extracts only designated human-language fields and leaves the note structures untouched.
11. Rhythm must remain mathematically coherent
Duration and divisions determine how MusicXML represents musical time. A translator should never modify values to make a local-language phrase fit above a note. Musical timing includes rests, tuplets, grace notes, dotted rhythms and ties that affect interpretation. Use a machine comparison of onset and duration information where tools permit it. Also review the visual notation, because timing may remain correct while a changed layout makes the measure hard to read. The translation’s job is to preserve the timing architecture while helping performers understand written directions.
12. Time signatures and key signatures
Musical meters and keys are core structural data. They do not change because the commentary is translated into another language. A target-language teaching note may call a key by a local convention, but the encoded key signature and pitch classes remain fixed. Be careful with German note nomenclature, solfège and other naming systems, because B and H can have different conventional uses. Avoid automatic substitution inside technical pitch-related fields. If the score includes a explanatory key label, review it as a musician would, while ensuring that notation software continues to present the same musical key.
13. Movement titles, subtitles and editorial titles
Movement titles may be poetic, descriptive, numbered or historically fixed. Translate a descriptive title when that is part of the publication brief, but distinguish the original title from an editor’s translation. A numbered movement or catalogue identifier must retain its association with the music. Works with well-known original-language titles may call for displaying both versions. Do not invent a literary interpretation as if it were the composer’s own wording. Keep work title, movement title, subtitle and dedication in their respective roles and test how they appear in both the conductor score and extracted parts.
14. Composer, arranger and lyricist credits
Creative credits are identity-bearing metadata, even when they appear as ordinary text at the top of a score. Names may have established transliterations, but a translated score must not change authorship. Preserve distinctions between composer, orchestrator, arranger, editor, lyricist and translator. An adaptation of a song text may require a new credit while the composition remains unchanged. Verify dates and copyright notices separately. In a multinational performance project, clear credit roles protect attribution and help musicians understand which edition they are playing. A localization update should not silently rewrite the ownership or creative history.
15. Performance directions and musical vocabulary
Directions such as dolce, marcato, sotto voce or with mute express musical intention, sometimes using Italian, French, German or the composer’s own language. An ensemble may prefer original terms, translated equivalents or bilingual notes. Decide the editorial policy before translating. A literal everyday translation can obscure the established performance meaning. The correct choice may depend on the target audience: professionals often recognise conventional Italian terminology, while beginners benefit from explanations. Protect any associated technical dynamics or timing settings. Human instruction can change language; the intended way of playing should not.
16. Tempo words and numeric tempo indications
A tempo expression may consist of a verbal indication, a metronome value or both. Translate the verbal portion carefully, but preserve numeric beats-per-minute and note-value references. ‘Fast’ is not a safe replacement for a nuanced marking such as Allegretto. A composer may use an idiosyncratic phrase that needs editorial annotation rather than a familiar generic tempo term. Check whether the music software uses the text for display only or also associates it with playback. A rendered score and a MIDI export should be compared so that localization does not cause unintended acceleration or slowdown.
17. Rehearsal marks guide ensemble navigation
Rehearsal letters and numbers are navigation points during rehearsals. They are not prose captions to rewrite freely. Preserve their sequence, placement and relationship to measures. If a score uses rehearsal mark A, a translator should not convert it to a local alphabetic symbol without coordination with printed parts and rehearsal scripts. A conductor calling out mark F expects every performer to find the same passage. Explanatory instructions beside the mark can be translated, but the shared navigation reference must remain stable across language editions unless an approved edition-wide renumbering has occurred.
18. Measure numbers and numbering conventions
Measure numbers help musicians identify passages, but anacrusis measures, repeated endings and multimeasure rests complicate their visual appearance. Do not recalculate them while translating a score. Test that part extraction preserves numbering and that any printed number offsets remain consistent with the source. Different applications may produce slightly different layouts, so measure numbering needs deliberate visual review. A translated annotation saying ‘begin at bar 42’ is useful only if bar 42 is still the same measure in all language editions. Navigation accuracy matters in live rehearsals and publication.
19. Repeats, voltas and endings
Repeat barlines, first and second endings, segno, coda and da capo instructions connect distant passages in performance. Their textual labels may require translation or adaptation to established symbols, but the encoded musical repeat behavior should remain unchanged. A literal string substitution can turn a familiar score directive into something a performer interprets differently. Follow the source’s intended sequence and compare repeat signs, ending brackets and directions in the printed score. If the export application loses a repeat relationship, resolve the technical issue separately. Translation cannot be allowed to disguise an incorrect playback route.
20. Dynamics symbols and words
Dynamics such as p, f, sfz and cresc. are conventional musical signs that may coexist with verbal instructions. Some are widely understood internationally and should not be translated as ordinary words. More unusual phrases can need an approved target-language rendering. Preserve whether the instruction is a dynamic level, an expressive change or an explanatory note. Test hairpins and direction placement as well as words. A dynamic mark attached to the wrong stave or played too early can change the music even if the text itself is perfect. Musical QA therefore requires reading the score in context.
21. Articulation and ornamentation
Staccato, tenuto, accent, fermata, trill and other signs encode how notes should be performed. They are generally not natural-language strings, although a textual explanation may accompany them. A translator should keep symbol and playback semantics intact. Do not replace a technical sign because its English label in a software tool has been localized. Where the audience needs an explanation, put it in a designated annotation or educational note. Compare articulation placement, especially for chords and multi-voice notation. Small changes can affect performance style and therefore exceed the authority of a translation brief.
22. Pedaling, bowing and instrument techniques
MusicXML can carry technique-related markings, including indications that apply to keyboards, strings, winds and percussion. Translation must consider the instrument and whether the phrase is an instruction or merely a technical encoding label. A string part saying sul ponticello and a piano part specifying pedal release cannot be treated as generic text. Consult a specialist glossary, preserve any encoded positions or symbols, and check the part layout. A technique translated too broadly may produce a different sound. When terminology lacks a clear target-language equivalent, a brief retained original term with explanation is often better than false precision.
23. Harmony symbols and chord names
Chord symbols are partly linguistic and partly harmonic notation. A change from a major seventh to a dominant seventh is not a translation. Preserve roots, degrees, alterations, bass notes and the functional relationships represented in the file. Styles of chord spelling may vary by musical culture, but converting among them requires explicit musical rules and testing. Roman numerals and Nashville numbers can also have specialized semantics. If the publication wants local-language theoretical labels, keep those separate from the underlying harmony representation. Compare a representative harmonic passage visually and, where relevant, aurally before accepting the target file.
24. Vocal text is an aligned musical layer
Lyrics are readable words, but they are connected to notes, verses and syllabic divisions. This article treats them as one element in a complete score rather than as the sole focus of localization. A translated lyric may need adaptation to singability, meaning and musical stress. That is a creative editorial decision, not simple replacement of characters in a note-linked text field. Preserve original musical timing and document any approved lyric adaptation. Test verse numbers, hyphenation and melisma extenders without changing pitch events. A parallel original-and-translation edition may be safer than silently overwriting the source.
25. Spoken directions and performance text
Some scores include spoken instructions, narration cues, stage directions or indications to an actor. These may carry timing, safety or dramatic meaning. Translate the audience-facing language carefully while preserving measure positions, cue links and any words that are actually part of the performed composition. A stage direction ‘enter after the bell’ is not a generic note if it determines synchronisation. Check the target-language wording against the rehearsal script and score. If translation changes the time needed to deliver spoken text, the creative team may need to approve adaptation; it must not be disguised as unchanged notation.
26. Percussion labels and unpitched instruments
A percussion score may use unpitched note representations, drum-set mapping and instrument-specific staff conventions. The printed label can be translated, but changing MIDI instrument assignments or notehead positions is not part of linguistic localization. A generic translation of ‘tom’ or ‘snare’ may also confuse a player if it fails to identify the actual instrument in the arrangement. Review both the part list and in-staff labels with a percussion specialist. Test imported playback and printed drum legend. Technical identifiers should remain stable even when the explanatory name is adapted for a target ensemble.
27. Tablature and nonstandard notation
Guitar tablature, percussion grids and contemporary notation may encode performance through representations that are not conventional staff pitches alone. A translator should identify how the instrument’s performance information is stored before editing nearby text. Fingerings, string numbers and fret positions are not words for localization. An explanatory heading such as ‘alternate tuning’ may be translated, but the actual tuning values must remain as specified. Review the output in the target notation application and, ideally, with an experienced performer. This prevents a file that passes XML validation from presenting an unplayable or misleading part.
28. Clefs, octave markings and ledger context
Clefs and octave-change marks affect how the performer reads pitch. A localization pipeline should protect them completely. Textual labels such as ‘8va’ may follow established musical conventions and can be explained rather than substituted without thought. A transposed score or condensed notation can already be cognitively demanding; adding unfamiliar localized shorthand may make it worse. Compare representative passages from the start, middle and end of every part. Make sure an export or import has not changed clefs or shifted octave instructions while rearranging text objects. The musical line must retain the same interpretation.
29. MusicXML’s compressed MXL packaging
Compressed MusicXML files are containers, not just single text files with a different extension. They can include a container definition and related files that notation applications use to identify the main score. Translate approved score text without breaking container paths, manifest relationships or encoding. Do not rename internal files impulsively to make filenames local-language friendly. Extract, process and repack with appropriate tools, then test the actual MXL in receiving software. A successful XML string replacement that leaves an invalid archive is not a successful delivery. Keep the unmodified source package for comparison.
30. XML schemas and validation limits
MusicXML 4.0 provides XML Schema definitions that are useful for validating document structure; the format’s older DTD representation is deprecated for this version. Run schema validation where available, but understand its boundary. A schema can accept a translated rehearsal instruction even when it is musically wrong, and it cannot determine whether a clarinet part’s name accurately describes the instrument. Combine structural checks with a musical comparison and visual inspection. Record the validator and schema version used. Correct software behavior is part of the evidence, not a substitute for musician review.
31. Extract text by element role
A safe translation process identifies which elements may contain human language: work or movement titles, creator credits, part names, words within directions and other approved annotations. It must not indiscriminately translate all XML text or attributes. Element context matters. The string ‘C’ can be a rehearsal mark, a pitch name, a chord root or a literal letter in a title. Provide translators with the surrounding part, measure and role so they can make sense of the string. Reintegration should map every translated segment to exactly one source location and detect missing entries.
32. Preserve IDs and links across exports
Score-part IDs, instrument IDs and other structured references provide continuity within a file. Translating them may detach displayed names from sound assignments or notes. Compare identifier sets before and after processing and investigate any changes. When software imports and exports MusicXML, it may rewrite IDs for internal reasons, so distinguish a controlled conversion from an unexplained localization change. Ideally, preserve the original file’s technical structure during translation. If a conversion is necessary, use a semantic comparison of linked parts and instruments to prove equivalence rather than trusting that the file still opens.
33. Layout is a performance concern
Part labels, expressive directions and titles can become longer when translated. A phrase that fit above a short measure in English may collide with dynamics or another stave in the target language. Test conductor scores and printed parts at realistic sizes. Look for hidden text, line breaks inside essential phrases, overlapping rehearsal letters, displaced system breaks and mismatched page turns. Layout should be improved without moving musical events or changing semantics. Some notation applications recalculate spacing automatically; that convenience needs human verification because a readable screen preview may still print poorly.
34. Page turns and extracted parts
An orchestral part is a working document used at a music stand, not merely a subset of a score. Long new-language instructions can push a measure onto another page and create an awkward page turn at a critical moment. Review page endings, multimeasure rests and cue placement in each individual part. Coordinate the translation with the ensemble’s publication requirements and rehearsal practices. If re-engraving is authorised, distinguish those layout edits from language edits in the change record. Preserve measure numbering so conductors can direct the entire ensemble consistently after localization.
35. Font support and glyph rendering
Music notation depends on special glyphs and text fonts. A target-language script may be unsupported by a score font or rendered with poor spacing. Use fonts that support the required characters without changing music symbols or smuggling font files into the score package. Test combinations of accented characters, CJK scripts, bidirectional text and musical signs. A missing diacritic can matter to a foreign-language singer, while a missing dynamic symbol changes musical instruction. Check the output as PDF or printed pages as well as in the editor because font substitution can happen at export.
36. Right-to-left text near notation
Arabic, Hebrew and other right-to-left languages introduce layout challenges when words appear beside left-to-right measure numbers, instrument abbreviations and note sequences. Avoid assuming that the whole score must be mirrored. The musical reading order, staff geometry and direction of time remain governed by the edition’s notation convention. Apply language-appropriate text direction within approved text objects and test mixed numerals and punctuation. Review printed and digital output with readers familiar with the target script. A visually reversed rehearsal label can cause practical confusion even if the encoded characters are valid.
37. Music-specific terminology glossaries
A useful glossary includes the musical function of each term, its source-language tradition, target-language equivalent and examples in score context. ‘Attack’ may refer to a note onset, while ‘release’ can concern a note, pedal or breath; those meanings need separate entries. Include instrument names, tempo nuances, technique marks and editorial conventions. List terms that should remain in Italian or their original form. A glossary should support musicians in different countries without forcing an unnatural universal style. Have the relevant performer or music editor review controversial choices before imposing them across a large score library.
38. Translation memory and repeated markings
MusicXML files contain many repeated instructions, so translation memory can save time. Yet a repeated English word may perform a different job in different parts. ‘Open’ can tell a brass player to remove a mute, identify an instrument setting or appear in an unrelated title. Store the element path, instrument, measure and editorial context with the segment. Approve reusable translations only when their performance meaning matches. A high match percentage is not proof of quality, especially when one wrong instruction may recur in dozens of extracted parts. Review in score context before accepting batch replacements.
39. AI and automated processing
Automation can extract text, preserve technical tokens, compare note-event hashes and flag missing translations. It can also produce plausible but musically inaccurate terminology. Keep generative translation outputs as proposals requiring relevant musical review. Never allow a language model to rewrite pitch, time or transposition fields while trying to improve a direction. Protect rights and distribution constraints for copyrighted scores when choosing external services. The strongest automation strategy is to narrow editable scope and make musical invariants measurable; it is not to assume software knows the composer’s intent.
40. Compare the score as music, not only XML
A source-target comparison should include part count, note and rest sequences, pitches, durations, measure structure, repeats, transpositions, dynamic and technique placement, and playback where appropriate. XML textual equality is not always necessary because applications can serialize equivalent music differently. But every unexplained musical difference is a reason to investigate. Use a representative playback render to catch gross changes, while recognising that MIDI playback does not reproduce every expressive nuance. A musician should still inspect the printed notation. Validation succeeds when technical structure and performance meaning remain stable.
41. Worked case: an international youth orchestra
A youth orchestra receives a conductor score with English instructions and musicians from several language backgrounds. The project provides approved instrument names, plain-language explanations of unusual techniques and translated programme notes. Rehearsal letters, pitches, transpositions and measure numbers remain the same. After reintegration, the library compares part lists and note events, then prints clarinet, horn, percussion and string parts. A rehearsal with representative players reveals that one abbreviation is ambiguous, so the display is corrected without touching music data. This is successful localization: the players understand their instructions while the ensemble performs the original arrangement.
42. Worked case: a multilingual school songbook
A publisher prepares a school songbook for learners in several countries. Each MusicXML file has a title, composer credit, explanatory notes, a piano accompaniment and vocal lyrics. The editorial team translates teaching instructions and movement descriptions, while a separate authorized process handles any singable lyric adaptation. Key signatures, melody and rhythm remain unchanged. Teachers test printed pages with children and review whether local terminology matches their curricula. Metadata distinguishes a translated explanation from a newly adapted song text. Keeping those responsibilities separate protects both the musical source and the educational purpose.
43. Worked case: a wind-band rehearsal package
A community wind band uses a score whose instrument labels include transposition information and whose percussion parts have specialised shorthand. Translators initially propose shorter target-language names, but the conductor notices one could be confused with a different instrument. The team retains the accepted orchestral name and approves a compact abbreviation. Technical instrument assignments and transposition data are unchanged. A test import into the band’s notation software confirms the score and parts remain aligned. The final package also includes a short multilingual guide to nonstandard rehearsal instructions, reducing confusion without editing musical events.
44. Handling ambiguous instructions
A composer might write an expressive direction such as ‘freely, but never rushed’ or ‘almost spoken.’ A literal translation can miss the distinction between expressive freedom and tempo instability. Ask whether the phrase is a composer instruction, a later editor’s gloss or a performing tradition. Where appropriate, preserve the original wording and supply an explanatory target-language rendering. Avoid replacing a nuanced phrase with a generic conventional term unless the composer or authorised editor approves. The change record should show what was translated and what remained original. Musical ambiguity sometimes requires editorial judgement rather than dictionary certainty.
45. A human review plan that matches risk
Different score elements need different reviewers. A linguist can assess grammar and cultural clarity; an instrumentalist can verify technique names; a conductor can judge rehearsal navigation; a music engraver can inspect layout; a publisher can verify rights and credits. Give each reviewer a defined responsibility. A change to a programme note usually has different consequences from a change to an instrumental direction above a note. Prioritise the latter for specialised review. Approval should reference the exact source edition, target language and exported file. This enables practical accountability without making every tiny punctuation change unnecessarily bureaucratic.
46. Deliver files with an edition trail
A localized score package should identify the language, source edition, translation date, editor and relevant version without suggesting that the musical work itself was newly composed. Provide a changelog limited to meaningful differences, such as translated instrument labels, explanatory direction notes or authorised lyric adaptations. Keep original source files and rights notices accessible. If the published score is accompanied by a PDF, verify that the PDF matches the MusicXML delivery. A future editor should be able to distinguish a translation correction from a source notation correction. That distinction is central to sustainable international publishing.
47. Ongoing maintenance and source corrections
Music is often revised after rehearsal. A composer may update a dynamic, replace a note or change a rehearsal mark. Such source changes must be tracked separately from improvements to translated wording. When a new source edition arrives, compare it against the version used by each language edition and identify affected text and notation. Do not blindly reapply an old translation if the musical instruction has changed. Keep a stable mapping for translatable segments and require musical revalidation after major updates. Localization is a living editorial responsibility when the repertoire itself continues to evolve.
48. The complete MusicXML localization checklist
Confirm MusicXML 4.0 source validity, application compatibility, edition and rights. Classify approved text fields and protect pitches, durations, measure structure, IDs, instrument mappings, transposition, repeats and numeric directions. Translate names and annotations in musical context; handle lyrics under a separate adaptation policy. Reinstate text through schema-aware paths, validate XML and compare the musical structure. Inspect conductor score and parts for spacing, fonts, navigation and page turns, then test imports and representative playback. Obtain appropriate musical and editorial approval before delivering. The objective is simple to state but exacting to achieve: different language, same music.
Conclusion and authoritative resources
Professional MusicXML translation respects the boundary between the music that is performed and the words that help people perform it. Scores are structured objects: the music, part identities and temporal relationships should not be collateral damage when a rehearsal instruction is localized. Musicians worldwide can share an accurate edition when technical invariants are protected and the language is reviewed in real performance context.
References: MusicXML 4.0 W3C Community Group Final Report; MusicXML XSD validation documentation; official transposition reference; companion guide to separating human displays from structured identifiers.