I can't upvote this enough, or love this guy enough for having the guts to make this into a video. In a former life, I had a phone job as a customer service rep. As cake as it was compared to my former, physical job, it was mentally stressful (even moreso than customer service in itself) because of the focus I had to hold for hours to even approach fluency. Most of the time I could do it by putting on my "overmodulated" or announcer's voice. Even then I'd have to pace myself carefully, and thoughtfully plan out my responses to avoid problem words. These days, I do something similar to the technique discussed in the video, along with breathing and pace control. Part of me is still frustrated that I have to manage and plan so carefully for something that most people do without thinking, but those are the breaks.