There's a helpfile that outlines this somewhat.

BUT even if it's not exact helpfile-lingo, all that matters to me is that the language sounds fitting of a giant with that int/wis. They probably shouldn't sound identical to drow/elves. That doesn't mean they have to sound retarded, and there are a lot of ways to do it, so show off your creativity in an attempt !

There is a really specific help file.

..here you go.

'FIRE GIANT SPEECH'
The speech of the fire giants is something that many may refer to as
'simple.' Having little patience for the rambling and often indirect
aspects of diplomacy, these cruel giants keep their sentences short
and to the point. In addition, they often underestimate the need for
secrecy, at times found being goaded into blurting out plans or schemes,
making them terrible confidants. Due in part to their strong reluctance
to trade, formal language skills within fire giant society are scarce
at best. This, unfortunately, provides them with little knowledge of most
common vocabulary, and their understanding of obscure words is nearly
nonexistent.

Got 'em

See, I just keep out the true problem:

This content censored due to ####girl-phobia

Sent from my Iphone

Here's some xp for your good giant talk.