well character doesn't matter too much as the abbr. is just made up since RPG's. Car / Char whatever. But in the case of computer languages calling 'char' a 'car' makes no sense.
pronounced [chahr]
Computing Dictionary
char programming
/keir/ or /char/; rarely, /kar/ character. Especially used by C programmers, as "char" is C's typename for character data.
[The Jargon File]
(1994-11-29)
Who cares? How often do you need to say "char", anyway?
If you want to avoid the argument, just say "character". You shouldn't be wasting saliva on someone who doesn't know what a character is, anyway.