I doubt multi-lungualism is taking up that much space in the weights. Languages are systematic, and most of them share a lot of features and can be compressed into the same representation together.
The real problem is all the random facts about the world that are not easily compressible, and you want the LLM to know a lot of random facts.
The real problem is all the random facts about the world that are not easily compressible, and you want the LLM to know a lot of random facts.