At this confusing point in the thread, I'd just like to muddy the waters even further:-

A lot of traditional music has Common Time (A large 'C') in the tempo signature part. I know that this is a sort of 4/4 time but no-one has ever been able to satisfactorily explain the difference to me.

One of the most used sources for English dance tunes at the moment is the very fine Hardcore English which has a long section of tunes Tunes in Common Time. Right these will all be marked with the 'common time' large 'C', won't they? Well, no, In fact none are marked in common time; they are all marked in 4/4...... apart, of course, from the ones that are marked in 2/4.

Then again, a lot of traditional tune manuscripts are tempo marked with a large 'C' with a vertical line through it or Alla Breve. Now I know this is a form of 2/2 but again what the difference is has never been satisfactorily explained to me.

I hope this post helps to make things less clear.
I think what has been written in this thread makes a strong case for learning the tunes that you want to play by ear.