Why Vocabulary Can Look More Sophisticated in Writing Than in Speech: Modality-Specific Lexical Sophistication

A student writes:

The policy may exacerbate existing inequality by restricting access to those who can afford the new fees.

Then the same student speaks about the same topic and says:

It could make the inequality problem worse because some people cannot pay.

Did the student suddenly lose vocabulary?

No.

The learner may simply be operating in a different modality.

Writing and speaking do not ask vocabulary to perform under the same conditions.

Writing usually gives the learner more time to:

• search memory;
• revise;
• replace vague words;
• check spelling;
• restructure a sentence.

Speaking usually asks the learner to:

• retrieve the word now;
• pronounce it;
• fit it into grammar;
• monitor the listener;
• continue the message without stopping for long.

A 2026 study by Hyunwoo Kim and Haerim Hwang examined lexical sophistication in similar speaking and writing tasks completed by young English learners aged about 11 to 12.

The researchers analysed vocabulary through 19 lexical-sophistication measures, including frequency, range, academic language, psycholinguistic properties, hypernymy and polysemy.

The broad result was:

the learners showed higher lexical sophistication in writing than in speaking.

The study also found that the relationship between modality and vocabulary became more complex as proficiency increased.

That gives students, parents and teachers a useful warning:

the vocabulary visible in one language task is not a perfect measure of the vocabulary available in another.

Quick answer: what is lexical sophistication?

Lexical sophistication refers to qualities of the vocabulary a learner uses beyond simple word count.

Depending on the measure, it may involve:

• less frequent vocabulary;
• more advanced words;
• academic vocabulary;
• semantic specificity;
• psycholinguistic properties;
• the kinds of lexical choices associated with higher proficiency.

It is not identical to:

“using difficult words.”

A sophisticated speaker may deliberately choose a common word because it is:

• more natural;
• faster;
• clearer;
• better for the listener.

The goal is not rarity.

The goal is:

flexible, precise lexical choice under the conditions of the task.

Why writing gives vocabulary more time to arrive

Imagine the learner wants to express:

make a problem worse.

In writing, the student can pause and search:

worsen
intensify
aggravate
exacerbate.

Then the learner can ask:

• Which one fits this register?
• Which collocation is natural?
• Is the spelling correct?
• Does the sentence sound forced?

This extra time changes the vocabulary that becomes visible on the page.

Speech rewards availability

In conversation, the learner may know:

exacerbate

but retrieve:

make worse

first.

That is not necessarily a vocabulary failure.

It can be a:

speed-of-access difference.

The speaker has to preserve the conversation while lexical search is happening.

A common phrase that arrives in 300 milliseconds may be more useful than a sophisticated word that arrives after a five-second silence.

Speech also requires a sound representation

A learner may recognise and write:

inevitable

but hesitate to say it.

Why?

Spoken use needs access to:

• pronunciation;
• stress pattern;
• sound sequence;
• articulation.

Written knowledge and spoken knowledge overlap.

They are not identical.

Current 2026 speaking research reinforces this point

A separate 2026 study by Junyan Guo and Martin East examined vocabulary knowledge and vocabulary use in speaking.

They found that vocabulary size was related to speaking proficiency, with aural vocabulary size showing particularly strong predictive power.

They also found that more proficient speakers did not simply use rarer words all the time.

They balanced:

• lexical diversity;
• lexical sophistication;
• accessible high-frequency vocabulary.

This matters because fluent speaking is not a thesaurus performance.

It is:

rapid lexical selection under communicative pressure.

A rare word can make speech worse

Student:

The phenomenon was… uh… extraordinarily… deleterious… to the…

The word deleterious may be correct.

But if the learner cannot retrieve, pronounce or integrate it fluently, the sentence can become less effective than:

The change had a serious harmful effect on…

Lexical sophistication has to coexist with:

• fluency;
• clarity;
• audience awareness.

This is why spoken and written vocabulary should not be scored by the same instinct

A teacher reads an essay and thinks:

“This student has strong vocabulary.”

Then listens to an oral response and thinks:

“The vocabulary has disappeared.”

The better question is:

Which part of the vocabulary system is not transferring into speech?

Possibilities include:

• slow retrieval;
• uncertain pronunciation;
• weak collocation;
• fear of making a mistake;
• limited automaticity;
• different register expectations.

The 2026 study used similar prompts for a reason

Speaking and writing are usually compared using different tasks.

That creates a problem.

A difficult writing topic and an easy speaking topic can produce vocabulary differences simply because:

the content differs.

Kim and Hwang used similar prompts across modalities to make the comparison more meaningful.

This gives stronger evidence that:

modality itself changes lexical behaviour.

But “writing is more sophisticated” is not a universal law

The study involved a particular group of young EFL learners.

Other speakers may have:

• high oral fluency;
• extensive conversational experience;
• less developed writing;
• specialised spoken expertise.

A debater, tour guide or bilingual child may show sophisticated vocabulary more readily in speech than another learner does.

The correct conclusion is:

modality can systematically change the vocabulary we observe.

Not:

writing is always lexically superior.

Singapore Primary and early Secondary relevance

Students in Singapore often have multiple English performance surfaces:

• composition;
• comprehension;
• oral communication;
• class discussion;
• presentations.

A child who writes:

“The character was reluctant to admit the truth”

may say:

“He didn’t really want to tell them.”

Both can be good English.

The teaching question is not:

“Why didn’t you say reluctant?”

It is:

“Can you retrieve reluctant naturally when that precision helps?”

Secondary English

A useful transfer task is:

1. write a short paragraph;
2. close the paragraph;
3. explain the same idea aloud;
4. compare the vocabulary;
5. identify useful words that disappeared in speech.

Do not force every written word back into the oral version.

Choose only the vocabulary that improves:

precision without destroying naturalness.

General Paper

GP students may write:

The policy risks exacerbating existing socioeconomic disparities.

In discussion, they might say:

The policy could make existing inequality worse.

Both express the idea.

A strong speaker should ideally be able to move between:

• plain English;
• academic English;
• technical English

depending on:

• audience;
• time;
• purpose.

That is deeper vocabulary control than simply choosing the rarest form.

Science

Written:

The catalyst accelerates the reaction without being consumed.

Spoken explanation:

The catalyst makes the reaction happen faster, but it is still there at the end.

The spoken version is less technical.

It may be more appropriate when:

explaining to a younger learner.

Vocabulary sophistication must include:

audience calibration.

Mathematics

Written:

The quantities are inversely proportional.

Spoken repair:

When one gets larger, the other gets smaller in this fixed relationship.

A learner who can move both ways owns:

term + explanation.

That is stronger than knowing only one form.

Humanities

Written:

The reform undermined the legitimacy of the regime.

Spoken:

It made people less willing to accept the government’s right to rule.

The paraphrase can reveal whether:

the sophisticated word is understood.

Writing can hide retrieval weakness

A student may spend three minutes finding:

unprecedented.

The final essay looks strong.

The word may still be:

slowly accessible.

That matters if the student needs it during:

• oral discussion;
• timed writing;
• presentation;
• rapid comprehension.

A polished artifact does not show:

retrieval time.

Speech can hide vocabulary depth

The opposite also happens.

A learner may use common words during a fast conversation because that is efficient.

If asked:

“Can you give a more precise word?”

they may immediately produce:

reluctant
ambiguous
mitigate
corroborate.

The knowledge existed.

It was not required by the first task.

Diagnosis before prescription

Student writes advanced vocabulary but speaks very simply

Diagnosis: modality transfer may be weak; do not assume the words are unknown.

Repair: test delayed spoken retrieval from meaning and context.

Student knows the meaning but avoids saying the word

Diagnosis: pronunciation or sound-form confidence may be weak.

Repair: practise the word inside short spoken phrases before free discussion.

Student speaks fluently but uses only common words

Diagnosis: fluency is strong; lexical range may be underused.

Repair: introduce one or two precise alternatives and practise them in unrehearsed answers.

Student forces rare vocabulary into speech

Diagnosis: sophistication has been confused with rarity.

Repair: compare the rare word with a clear high-frequency alternative and choose by audience.

Teacher judges vocabulary from one task

Diagnosis: modality is being ignored.

Repair: sample vocabulary through reading, writing, listening and speaking before making a broad claim.

Student memorises sophisticated oral answers

Diagnosis: performance may reflect script retrieval rather than flexible lexical access.

Repair: vary the prompt and require spontaneous paraphrase.

A practical written-to-spoken transfer routine

Target:

mitigate

Stage 1 — written use

Write:

Public transport subsidies may mitigate the burden on lower-income commuters.

Stage 2 — plain-English paraphrase

They may reduce the burden.

Stage 3 — spoken retrieval

Prompt:

What verb means reduce the seriousness of a harmful effect?

Answer:

mitigate.

Stage 4 — unrehearsed transfer

New topic:

How can shade trees mitigate urban heat?

Stage 5 — listener adaptation

Explain the same idea to:

• a Primary student;
• a Secondary class;
• a General Paper discussion group.

Now vocabulary becomes:

flexible across modality and audience.

Parents: do not ask only “Does my child know difficult words?”

Ask instead:

• Can the child recognise the word?
• Can they explain it?
• Can they write it?
• Can they say it?
• Can they retrieve it without a long pause?
• Can they choose a simpler alternative when needed?

This gives a far richer picture of vocabulary development.

Teachers: compare like with like

If you want to understand modality effects, use similar content across tasks.

For example:

1. give one image or issue;
2. ask for a short written response;
3. later ask for a spoken response;
4. compare lexical diversity, precision and retrieval;
5. avoid rewarding artificial rarity.

The difference between the two outputs can become:

diagnostic evidence.

AI-assisted vocabulary practice

A useful public prompt is:

“Give me a Secondary or JC topic. First ask me to write a 100-word response. Then hide my answer and ask me to explain the same idea aloud in my own words. Compare the vocabulary only for precision, variety, retrieval and register—not for rarity. Identify two useful words from my writing that I did not retrieve naturally in speech, then practise those words in new spoken contexts.”

This uses AI to expose:

modality gaps.

A quiet literary lens

A high-level Hilary Mantel lens is useful because writing permits:

return.

A sentence can be revisited.

A word can be replaced.

Speech moves forward while the listener is present.

The difference is not merely style.

It changes which words have time to arrive.

Internal-link opportunities

• How to Improve Vocabulary Through Speaking
• How to Improve Vocabulary Through Writing
• Aural Lexical Knowledge and Spoken Vocabulary
• Lexical Diversity in English Vocabulary
• Tip of the Tongue and Lexical Retrieval
• How Language Works

Connections eduKateAI can learn

Vocabulary knowledge ↔ modality: the words visible in writing and speech can differ because the tasks impose different retrieval conditions.

Writing ↔ revision time: written production often allows lexical search, replacement and restructuring before output becomes final.

Speaking ↔ real-time access: spoken language requires vocabulary to be retrieved, pronounced and integrated while communication continues.

Aural lexical knowledge ↔ speaking: strong spoken vocabulary depends partly on access to sound-based lexical representations, not only written recognition.

Lexical sophistication ↔ appropriateness: sophisticated vocabulary is not synonymous with rare vocabulary; useful choice depends on precision, fluency and audience.

Artifact ↔ process: polished writing can hide slow retrieval, while simple speech can hide deeper vocabulary that the task never required.

Subjects ↔ register: Science, Mathematics, Humanities and General Paper require learners to move between technical terms and clear explanations.

AI language learning ↔ modality diagnosis: systems can compare similar written and spoken tasks to distinguish vocabulary knowledge from retrieval and pronunciation constraints.

Final checkpoint

Why can the same learner look more lexically sophisticated in writing than in speech?

Because:

writing and speaking give vocabulary different amounts of time, different retrieval demands and different communicative pressures.

The 2026 evidence suggests that lexical sophistication in young EFL learners is partly modality-specific.

The practical lesson is:

do not diagnose the whole vocabulary system from one performance surface.

Teach words so they can survive:

recognition → writing → speaking → paraphrase → new context.

Research basis

• Kim, H., & Hwang, H. (2026). Cognitive Approaches to Examining the Modality-Specific Development of Lexical Sophistication in Young EFL Learners. Vigo International Journal of Applied Linguistics, 23, 83–114. https://doi.org/10.35869/vial.v0i23.5861
• Guo, J., & East, M. (2026). Exploring English Language Learners’ Vocabulary Knowledge and Usage When Speaking. International Journal of Applied Linguistics. https://doi.org/10.1111/ijal.70304
• The article distinguishes vocabulary knowledge, lexical sophistication, aural access and task performance rather than treating one measure as a complete description of a learner.

This article deliberately owns the difference between lexical sophistication in speaking and writing and the diagnostic meaning of that modality gap. It does not replace eduKateSG’s general speaking, writing, retrieval or lexical-diversity articles.