Joining the Official Owlcat Games Discord can help you connect with other Bosnian players who might have shared custom files. How to Install Custom Subtitles
Search the Discussions tab for keywords like "Bosnian subtitles" or "prijevod" to see if local groups are collaborating on a patch. Rogue Trader subtitles Bosnian
Since Bosnian is not always a default option, players often turn to community-driven projects. Joining the Official Owlcat Games Discord can help