Oh, isn’t that interesting! The Japanese is simple and precise but the straightforward English translations are ambiguous. The Japanese makes it clear that it’s not that he likes English as well as some other languages, it’s that he is one more person who likes English. But “I like English, too.” or “I also like English” could mean either, though in spoken English you could stress either “I” or “English” to make clear which. Otherwise you would have to say something like: “As well as some other people, I also like English.” And yet Japanese has a reputation for being vague!
Japanese only feels vauge out-of-context because sentences often drop the subject or object, or things like pronouns aren’t commonly used. But in the middle of a conversation, the missing context will usually be obvious. English has so many ways to word the same thing that it’s a lot easier to be vague or unclear on purpose.
The way English can emphasize individual words within a sentence to give different meaning also adds even more complexity; you can occasionally find this in Japanese (in manga you’ll see dots over the emphasized words) but it’s not even remotely as prevalent.