That's a good question, so I decided to dig up all the japanese-translated quotes I have by Ultimecia:

1. Ultimecia: Your feelings, I shall summon the most powerful of things [from them]! The more strongly you feel, that will be what shall torment you. Fufu.

2. Ultimecia: Fufu. Are your memories fading to nothing? This is not the dreadfulness of the true GF. The GF's true ferocity, let me instruct you [in it]! That power, show it to them! Griever!

3. Ultimecia: The introductions are over! Now, I shall junction myself to Griever!

Unfortunately, she doesn't say any words beginning with strong c's (like compression or curse) so it's hard to deduce anything from this. And "fufu" merely signifies laughter, so that's not anything to be considered...