The Vulcans likely gave humans more than starcharts. I wouldn’t be surprised if Vulcans also gave humans rather large databases of other languages. There are probably also algorithms for determining languages based on known samples.
For that one planet that Archer condemned a species to die while having an easily treatable disease with their technology, first contact likely started with the person getting them in a language that the universal translators could understand then running all verbal and text communication it could through Enterprise’s computers to come up with a rough translation.
We know that the Universal Translator isn’t perfect. ST:VI had the scene where Uhura had to speak in Klingon because the Universal Translator would be detected. TNG had the translator be worthless when a species spoke only in memes. DS9 also had the episode where the genetically augmented group gained insight by listening to Weyoun in Dominionese instead of translated to English.
