(Properly speaking, this should be a non-repeat, but in this case, the non-repeat happens to be Learnt English From Watching Television, and as this refers back to a couple of the repeats, this one and First Contact, I’m going to adopt a general policy of moving those up in advance when I have the text, just to keep the references simple.)
Aliens Speaking English: Everyone uses translators; the sufficiently advanced use neurocomputer translators that are basically prosthetic language centers for the brain, and the less advanced the handheld or worn kind, but the effect is much the same. All of these can at the very least translate to and from Trade, an extremely simplified pidgin (loosely based on Eldraeic I) that serves as an interlingua, but those who know they need to communicate with a particular species/polity/culture will purchase a proper linguistic corpus for their language; it’s more polite. Truly courteous people even go to the trouble of actually learning the nuances of the alien language themselves, assuming they can manage the phonology; doing so is something of a universal signifier of non-xenophobia and willingness to Make The Effort.
And no, there’s no such thing as a universal/self-teaching translator. There’s just years of work by teams of highly dedicated linguists.