If I’m reading your post correctly (which may be a big assumption): you are asking how to translate from specific languages into OMOP concepts? Yes?
If <500k terms, you could use Google Translate APIs to batch up unsupported languages and translate to a string in a supported language. Maybe someone from @nigam’s team could give you some insight on this approach. If you’re very ambitious, you could be the first to pioneer an OMOP vocabulary amendment to create concepts from each mother tongue into the common tongue. @Dymshyts @Christian_Reich @aostropolets could give you guidance. I would imagine our colleagues in Spain may have some concepts you could leverage for Valencian. @Rijnbeek could help connect you.
But more intriguingly, what kind of data is this? A Ugandan dialect, an Athabaskan dialect and A Catalan dialect. What do you map from?