Yes, there clearly are galactic languages, but equally the lingua franca of space travel in the -areas we see- seems to be English. Looking at countries with current or incipient space programs, this doesn't seem too unreasonable. In many cases English is already a de facto elite/technical lingua franca, as in parts of India and increasingly China.

Looking at current international cultural exchange in things like...Eurovision, English is a bit more prominent than one might expect too. ;)

Escobar has what looks like Spanish as an official/local language, but English as another language the people we see speak to Betans and Barrayarans.

Miles -doesn't- speak galactic languages, so I think it can be assumed that people are talking to him in a language he understands unless he's specifically mentioned as having a translation earbug. There's circumstances where he clearly -doesn't- have any extra gear, such as Dagoola!