I am selecting French or English depending on the phase of the moon and rarely see any difference in waiting times. My impression is that a significant fraction of call center agents are bilingual.
I have also noticed longer wait times lately. There are so many things I could have done online if AC IT was not so incompetent. Like, after you upgrade a Latitude pass segment with a SWU and need to cancel the trip, it cannot be done online. How stupid is that. One hour worth of my time trying to save a pass credit.