Originally Posted by: Slipin LizardClarkey, just a quick answer to your quoted question... its a way of breaking down a 4/4 beat. When you hear someone introducing a song tempo, "A one, a two.." they are verbally counting out a tempo (technically a rhythm too, but lets just stick with 4/4 right now). So another way we could verbally count out a tempo would be "one two three four"... maybe you've seen or heard a drummer click their sticks together to set the tempo and count the band in.
"One-e-and-a" is also a verbal count, but instead of tempo, what you're talking about is breaking the 4/4 count down... into:
quarter notes: 1 count for every beat, spoken "one two three four".
eighth notes: 2 counts for every beat, spoken "one-and two-and three-and four-and
eighth note triplets: 3 counts for every beat, spoken "one-and-ah two-and-ah three-and-ah four-and-ah
sixteenth notes: 4 counts for every beat, spoken "one-ee-and-ah two-ee-and-ah three-ee-and-ah four-ee-and-ah
There are many reasons why someone may wish to count out loud, whether to themselves, or teaching someone in a lesson, but most common are:
-to simply clarify the breakdown of of the beats within a measure... "its eighth notes... one-and two-and three-and four-and..."
-to emphasize where a certain note or strum falls within a measure... "its sixteenth notes... you have to hit the note on the ah of one, one-ee-and-ah..."
-as mentioned before, to explain a rhythmic feel, like a shuffle or waltz.
Hope this helps!
Couldn't have explained it any better!