use of "as"

I would expect to see a but there.

Many thanks for the quick response Blue Jay, is it definitely incorrect to use "as" in that context and if so ( and it's not too much hassle to explain ) could you briefly tell me why? I'm thinking it's something to do with the bit after "as" not being a reason for the bit before "as" but I don't know to express that correctly.

"As" is wrong there, and your reasoning is correct. "As" would be appropriate as an alternative to "because", giving an explanation of the fact in the first part of the sentence. In this case, the second part of the sentence ("Jim doesn't understand the difference") doesn't explain the first part ("people are taught the difference"). You could have 'Most folk who learn English are taught the di

Many thanks for that Blue Jay, much appreciated!