what are the different languages spoken in Gulliver's Travel

He learns the languages of all the different cultures he encounters. This includes the language in Lilliput, the language in Brobdingnag, the language in Laputa and the language of the Houyhnhnms.

However, he clearly knows far more languages than he learns on his travels. For example, in Glubbdubdrib he brings back a whole host of dead people, including Alexander the Great, and converses with them. We can therefore assume that he is fluent in Latin and Greek as well as English.

He also poses as a Dutchman on his voyage to Luggnagg, so he clearly knows Dutch as well. We are never told whether he understands Japanese