https://github.com/CatholicOS/bibleget-api/blob/master/README.md
The API's available versions:
https://query.bibleget.io/v3/metadata.php?query=bibleversions
There's a languages filter in here as well. See the bottom of
https://query.bibleget.io/v3/metadata.php?query=biblebooks
BibleTime is a completely free Bible study program, built for Linux, Windows, FreeBSD and Mac OS X. BibleTime contains over 200 free Bible texts, commentaries, dictionaries and books, provided by the Crosswire Bible Society via the SWORD programming library.
Regarding your specific project, there exists a mature software called BibleTime that enables parallel reading of any arbitrary number of bible translations including across any languages you have the text for. The same tool enables downloading of many biblical texts for a large number of languages; mostly free or public domain translations but also some licensed translations like NASB.
-- a buddy