The precise meaning of the sentence 他會說中文 (t¯a hu`ı shu¯o zh¯ongw´en/ He can speak Chinese.) is that he is able to speak Chinese due to deliberate learning.
Although the following sentences look similar to the sentence mentioned above, the message they convey are quite different: 他能說中文 (t¯a n´eng shu¯o zh¯ongw´en/ He can speak Chinese.) indicates his physical ability to speak Chinese, while 他可以說中文 (t¯a k´ey˘ı shu¯o zh¯ongw´en/ He can speak Chinese.) implies that he is able to speak Chinese by possibility through permission.
Reference: Chinese: a linguistic introduction by Chao Fen Sun
