Human QA for generated audio

Generated audio can sound fluent and still teach the wrong thing.

Testheard matches your audio with qualified human ears to catch pronunciation, code-switching, cultural, tone, and performance problems before your learners hear them.

Audit 30 minutesView sample report

Built from producing more than 72 hours of bilingual generated audio across Brazilian Portuguese, Spanish, Mandarin, Korean, Japanese, and English.

Driftspeak, Chapter 12PT-BR to EN-GB
Unreviewed

Vou pegar o ônibus mais tarde. I’ll catch the bus later.

The sentence is correct. The voice is not.

How it works

One quiet path from raw audio to a release you can trust.

  1. Upload
  2. Match
  3. Listen
  4. Correct
  5. Verify
  1. 01Send the audio and context.
  2. 02We match the right ear.
  3. 03Receive timestamped corrections.
  4. 04Regenerate and re-check.

Two disciplines, one unified report.

You never buy separate language and performance products. Testheard staffs both and delivers a single verdict on whether the audio is safe to release.

Language

  • Pronunciation
  • Phrasing
  • Stress
  • Code-switching
  • Cultural credibility

Performance

  • Tone
  • Pacing
  • Emphasis
  • Continuity
  • Listener experience

Native Ear Audit

£245

  • 30 finished minutes
  • One language pair
  • Language and performance review
  • Timestamped correction guidance
  • Three working days
Start an auditCorrection re-check, £85

Payment follows acceptance of your brief, never before.

Sample report

Every finding is located, explained, and verifiable.

A timestamp, a clear explanation, the likely cause, and a correction you can act on. This is one finding from an illustrative Driftspeak audit.

View the sample report
00:18:42Pronunciation and regional authenticityMajor
“vou pegar o ônibus mais tarde”
Finding
The Brazilian Portuguese pronunciation becomes noticeably Anglicised across the final clause. The vowels in mais tarde carry English stress and would feel unnatural to a Brazilian listener.
Listener impact
A beginner may absorb the Anglicised vowel pattern as the correct model, learning an accent no Brazilian speaker would use.
Likely cause
The model appears to follow English phonetic stress after the code-switch and does not fully return to the Portuguese register.
Suggested correction
Regenerate the clause separately using the original PT-BR reference voice, with phonetic guidance for the affected phrase.
VerificationVerifiedLanguage · High confidence

Origin

We produced more than 72 hours of bilingual generated audio for Driftspeak.

Generation scaled quickly. Verification did not.

Testheard was created to turn qualified human listening into a repeatable production workflow.

Send your first 30 minutes.

Audit 30 minutesThree working days. £245.