I ended up getting this game 100% correct, and I was easily able to do the setup. However, I didn't leave the game feeling confident in my work because nowhere (that I could determine) in the stimulus does it explicitly say that each language must be spoken by at least one of the experts.
As far as numerical distributions go, it states:
1. Each presentation is in exactly one of the four languages.
(This means that each presentation is spoken in a language and that language must be from the following options.)
2. Each expert speaks exactly one of the languages
(Meaning that no expert can speak more than one language)
3. Exactly two of the presentations are in the same language as each other
(meaning exactly one language is spoken twice by two different experts)
HA, okay there's the answer to my question. If there are five experts that must speak a language, four languages, and one must be repeated exactly twice, then it must follow that the other three languages must be spoken once by the remaining experts. Concluding a 2-1-1-1 distribution.
Okay I'll post this anyway because writing it all out literally forced me to answer my question