"He can speak five languages."
Translation:Il peut parler cinq langues.
The sentence makes sense and I would guess here that the meaning is similar to "Il sait..." (not a native speaker so not sure). But for other verbs, the meanings can be different. I remember my French teacher saying "Il sait jouer au tennis" means he can play tennis because he knows the rules, etc., but "Il peut jouer au tennis" means he is physically able to play.