Hey there, I would click here and give the design journal on languages and communication a read. (Particularly you may like the "Languages" section)
In short though, yes there will be varying levels of language comprehension. Loosely they will range from knowing nothing, to basic vocab, to complete comprehension.
Also yes, translators are completely possible. The To'resk themselves in the lore write up often take on the task of translating for the Janoa as they refuse to learn other languages but their own (historically speaking) How this plays out in game, is up in the air, but you can certainly learn multiple languages and take on the role of translator.
Also, welcome to CoE :D