On a similar note, I've noticed a difference in use of
a/
an before abbreviations. I don't think there are any "
official" rules on this, because it's never a problem orally.
Let's look at an example.
In my work, we talk about System-on-a-Chip, commonly abbreviated to SOC. Consider a textbook saying one of the following:
a) Blocks of a SOC are connected ...
b) Blocks of an SOC are connected ...
As far as I can see, both are perfectly legal. The difference is how the author would pronounce the abbreviation. SOC would be pronounced respectively:
a) sock
b) ess-oh-see