Subtitles need no dubbing: a transcription, optionally translations, and subtitle outputs.

Subtitle files in several languages

English SRT, Spanish SRT and French WebVTT for every input:
lecture-01.mp4 gives lecture-01.en.srt, lecture-01.es.srt and lecture-01.fr.vtt. The default name is ${name}.${lang}.${ext}; set nameTemplate for another. A cue where the speaker changes starts with >>. To use another mark, or none, see Speaker changes.

A transcript only

Subtitle streams inside the video

Selectable subtitles in the MP4, with the input’s own audio. The item, in the S3FolderOutput’s items:
In Matroska, set "subtitleCodec": "subrip" on each track.

Subtitles with a dub

Subtitles and dubs combine in one project: a translation with ttsOptions can feed both a dub track and a subtitle output.