Changing word is just an expedient, instead, you should learn how to use speech techniques such as prolongations, Gentle Speech, and etc to overcome blockages. Or metronome: Download a metronome app and practice reading materials following to the pace of it. The steady regimen of metronome is about 15 mins per day, 5 days per week and after 8 weeks you are likely to witness the effectivenesses, and remember that pace should increase from 90 bpm to 120 bpm gradually along the process. Hope that can help u a lot