While Harry Potter is a wizard, he doesn't have the ability to translate languages magically. The wizarding world uses a universal language called "Parseltongue" which allows them to communicate with snakes. This is a specific language, not a means of translation.
There are some characters in the Harry Potter series who can speak multiple languages. For example, Hermione Granger is fluent in French and can read Ancient Greek and Runes. However, there's no indication that any character has the ability to translate any language they encounter.
So, to answer your question, Harry Potter cannot translate languages. He can only speak Parseltongue, the language of snakes.