Many years ago, I compiled a list of my "red" words (very fluency problematic) and "yellow" words (somewhat fluency problematic). I list my red and yellow words below. FWIW, my little company has an app that collects your own personal list of problematic words, and an app that generates 'sanitized' stories for you to recite which do not contain any of your defined problematic words. So these are stories that you should be able to recite fluently. If anyone is interested in trying out these apps (for free), please contact me at [steve@fluencyai.net](mailto:steve@fluencyai.net) Red words: Center, congratulate, congratulations, constitution, constitutional, Czechoslovakia, go, get, going, physics, physicist, Remy, security, situation, system, such                    Yellow words: can, central, check, come, convenient, could, industry, just, let, like, necessary, perform, prefer, put, register, registration, should, stutter, such, they’re, to, whether, which, wish, would