Working in bulk

Hi, is there a way to merge audios in bulk to files in bulk? I have 500 files with English audio and another 500 similar files with matching names but with Japanese audio and I want to merge them so each file would have both audios. how can I do that?

Welcome!

With a shell such as bash or zsh this is rather easy, something along the lines of:

for mp3_en in english/*.mp3; do
  mp3_ja=japanese/${mp3_en#english/}
  mkvmerge -o output/combined.mka --language 0:en ${mp3_en} --language 0:ja ${mp3_ja}
done

You can do similar things with cmd.exe; I just cannot help you with the syntax.

Alternatively there are third-party GUIs that can do a limited set of things; see this page.