The only trek species that has to learn a language to interact with The Federation would be the Tamarians, since theirs is the only language that completely defeated the universal translator (they speak in metaphor, instead of directly)
Honorable mention to some of the aliens they interact with in Enterprise, before the Universal Translator was fully working. Though technically they weren’t the Federation yet.
Has Star Trek ever had a Klingon character that did not speak what ever the Federation is speaking? Only Klingon?
Tons. Most of them aren’t speaking English in the first place, it’s the Universal Translator
The only trek species that has to learn a language to interact with The Federation would be the Tamarians, since theirs is the only language that completely defeated the universal translator (they speak in metaphor, instead of directly)
Honorable mention to some of the aliens they interact with in Enterprise, before the Universal Translator was fully working. Though technically they weren’t the Federation yet.