Video captions: speech, interface language and translation
The website's language, the spoken language and the caption language are three different things.

Transcription is not translation
English speech with English captions is transcription. English speech with captions in another language also needs translation that preserves meaning, context and reading time.
What changing the language does
Changing Ozavio's menu language changes the interface. It does not automatically translate the video's subtitles. Check the options actually available in your project.
Current clipping support
The current transcription path is configured for English. Additional spoken languages and automatic translation are not presented here as verified clipping features. Even English transcripts need review.
Review with someone who understands the speech
Check names, terminology, meaning and timing against the original. Watch the export on mobile and review each language switch carefully. Fluent-looking text can still contain errors.