What is the difference between 会 and 说 in 你会英文吗？ vs. 你说英文吗？ What is the difference between the characters 会 (huì) and 说 (shuō), for example in these simple closed questions:

你会英文吗？ [Nǐ huì Yīngwén ma?]
你说英文吗？ [Nǐ shuō Yīngwén ma?]

I am wondering since various online resources give both of them as examples of the verb 'to speak' or 'to say' but I want clarification on whether this is correct and if there are any rules on when to use them in different contexts.
This is exactly what I stuck in at the very early stage of learning Mandarin!

会 is usually used as an auxiliary verb (mean "can", "will", etc...) and thus take a verb after that, but it can also function as a verb, to mean "know" or "understand".

That's why in your example, both mean "Do you speak English?". 

Also, if you want to use 会 as an auxiliary verb, you can also say "你会说英语吗？".