Sentioscope

Speech and voice controls, as each vendor documents them

HeyGen: lip-sync named, inside a translation sentence

Lip-sync appears in one place: the sentence describing video translation for thirty or more languages, with voice cloning beside it. It is named as part of a workflow rather than explained as a mechanism. As of 2026-09-22.

A claim that lives inside one sentence about translationLip-sync is named alongside voice cloning in the description of video translation. That is the harder case, because new words of a different length have to arrive over footage that already exists.Where the lip-sync claim is documentedVideo translationNamed, with cloningMouths changed over existing footage, forthirty or more languagesGenerating from a scriptNot addressedWhether the same behaviour applies is notstated anywhereWhere a claim appears decides what it covers
Fig. 1 Extending the sentence to cover generation in the original language would be reading past what it says.
HeyGen on lip-sync, statement by statement. Read from the vendor's API quick start on 2026-09-22.
What the documentation settlesWhat it leaves to a take
Video translation is documented for thirty or more languages, with cloning and lip-syncWhat drives the mouth during that translation
A text to speech endpoint turns a script into speech audioWhether lip-sync applies to speech from that endpoint too
A clone is instant from one recording, or professional from twenty minutes or moreWhether a cloned voice aligns better than a catalogue one

Inclusion rule. Only statements found on the vendor page named in the caption, and only ones bearing on this one field. Nothing here is filled in from generated output. Order. In the order the statements arrive on the vendor's page.

1Where a claim appears decides what it covers

Because lip-sync is mentioned only in the translation sentence, the safe reading is that it is documented for translation. Whether the same behaviour applies when a video is generated from a script in its original language is not stated, and assuming it does would be extending the sentence past what it says.

That is a narrow reading and a deliberate one. This column has three grades of answer, and a claim attached to one workflow is worth less than a driver named for the product as a whole.

2Translating a mouth is a harder problem than generating one

Translation means new words of a different length arriving over footage that already exists. The mouth has to be changed rather than created, and the surrounding face has to stay put. Naming lip-sync in exactly that sentence is therefore a claim about the harder case.

It is also the case where failure is most visible, because a viewer has the original performance's rhythm to compare against. Nothing published says how the trade is made, so the cell records the claim and not a mechanism.

3The others that name the feature and stop

Three more entries put lip-sync on the page without saying what moves the mouth. One of them names it only in a warning about where it stops holding.

  • Kling AI — named, with nothing driving it.
  • PixVerse — named as the endpoint's purpose.
  • Sora 2 — named only where it fails.
  • Languages
    Video translation is documented for thirty or more languages, with voice cloning and lip-synccounted on the translation endpointHeyGen, API quick start / recorded 2026-09-22
  • Voice source
    A voice clone is instant from one recording or professional from twenty minutes or more, and is then passed as a voice idtwo enrolment routes with a thresholdHeyGen, API quick start / recorded 2026-09-22
  • Audio source
    A text to speech endpoint turns a script into speech audio as a step of its ownan endpoint apart from the pictureHeyGen, API quick start / recorded 2026-09-22

4Sources

Read from the API quick start at developers.heygen.com on 2026-09-22. The same column across every entry is on lip-sync; everything this vendor publishes about speech is on HeyGen. What counts as documented is on how read.