Yeah, I'm exactly the same way. What's weird is that once the other person understands the word I'm trying to say and says it for me, it suddenly becomes easier for me to say the word. Similarly, at restaurants for example, pointing to the menu while I'm ordering something so that the waiter knows what I want allows me to say the word without much trouble(does that make sense? oh well). I think it really reinforces the idea that stammering is all mental.