At a time when my stammer was severe, I had very fluent conversations with a deaf colleague. She relied on lipreading so if I spoke with my face contorting the way it did she wouldn't be able to understand what I was saying. Instead I simply mouthed the words at a pace slightly slower than normal speech and accentuated mouth movements to make it easier for her to read my lips. I couldn't have conversations like that with anyone else at the time. I later realised that sometimes when I have difficulty with speech, part of the problem is that I am mumbling, and if I am more deliberate with my diction, speech becomes a little easier.