The trick part is that they 会，可以and 能 all mean "can" but they are used differently. Let me try to explain the differences. 会 means 'will' or 'can' (ability) and refers to something someone can do(from knowledge[because he/she learned how to]) example: 他会说英语 - He can speak English. You wouldn't use '能' here. 能 means "to be able to" but refers to physical ability. e.g. 她上星期感冒，喉咙真痛，所以不能唱歌。现在能唱歌了(She had a cold last week [and] her throat was really sore, so she was unable to sing. [But] now she can) This is probably a better comparison: a guy who has never played soccer would say: '我不会踢足球“(i can't play soccer) a guy in a wheel chair would say "我不能踢足球”(i am unable to play soccer)- because he cant move his legs(due to physical inability) 可以 means "can" also but it is used as: 1) - asking for permission: 借我一支笔，可以吗？-may I borrow a pen? 2 as in an alternative idea. Lets say you wanted to go to the library with your friends, but had no idea it was closed. At which point your friend says '没关系，我们可以去博物馆'that's okay, we can go to the museum. Silly example, but hopefully it clears up any confusion)

这三个句子中“他会说英语”所表达的程度是最高的。 “他能说英语”和“他可以说英语”表达的意思是相同的，都表示这个人会说一点英语，但不一定说的好。 你体会下下面这些句子的含义： A:你会说英语吗？ B:我能说一点，但是不太好。 有时中国人为了表达谦虚，都喜欢说我能说一点英语或是我可以说一点。

The first show that the person's chinese ability is higher than the second and the third.

"会说" is most commonly used. 他会说英语 -他不但会说英语，还会说汉语。(able to) 能 and 可以 also means "it's allowable to do sth.". -他能说英语，但说得不好。(able to) -在汉语课上不能说英语。(you shouldn't speak english on a chinese lesson.) -他很厉害，可以说七门外语。(able to) -在汉语课上虽然可以说英语，但要少说。(you can speak english on a chinese lesson, but you should't speak it too much.)

会，means he have a ability, or he have a skill, he know english, so he can speak english. 能，means get permission so u can do or didn't get the permission so u can't do, for instance:he hasnt' been allowed, so he can't speak in english, but it didn't means he doesn't know english. 可以, equal to 能. usually, we use 会 to express he know english, or u can use 他懂英语 instead of 他会英语, both the same meaning. 能 and 可以，i can only think of one place to use it: in english class, 你能说英文，不能说中文，in chinese class, 你可以说中文，不可以说英文