Word substitution is a very common trait that people who stutter have. In fact, we spend a LOT of effort (physical/mental) on trying to hide our stutter and word substitution and avoiding situations is how many of us cope with it. It's EXHAUSTING. Most SLPs and stuttering organizations now suggest that we should stutter freely, and not hide it. I like this idea, but it's easier said than done. I personally cop out by always appending "my name is..." before saying my name and saying it slowly so that I can "ride the wave" of fluency and say my name.