Acts 21:40: "When he had given him permission, Paul, standing on the stairs, motioned to the people with his hand; and when there was a great hush, he spoke to them in the Hebrew dialect . . . "
Acts 22:2: "And when they heard that he was addressing them in the Hebrew dialect, they became even more quiet. . . ."
Acts 26:14: "And when we had all fallen to the ground, I heard a voice saying to me in the Hebrew dialect, 'Saul, Saul, why are you persecuting Me? It is hard for you to kick against the goads.'"These verses simply say "Hebrew" (Greek Ἑβραΐδι), but it is well known that the Greeks did not distinguish well between Hebrew and Aramaic, which were otherwise closely related languages. There is no reason to doubt this information. It is supported by other details found in Paul's writings and the style he exhibits in them, such as the omission of the article in places due to the influence of the Hebrew language.
Paul clearly handled the Greek language with ease. He was able to express his ideas with great clarity. He even created neologisms and gave new meanings to existing words. It is also likely that Paul knew some Latin, although we have no direct evidence saying so.