I think its because once they said it the pressure is no more, but it comes back in the next word and the cycle continues. I sometimes wish they continue my words if they know what I mean, I remember my physics teacher this year asking me who was my previous teacher (same school) and I really struggled to say his name and everyone knew who he was but out of respect they didnt tell, I wish they helped me I struggled for like 50 sec and it was awkward for the class the teacher and me obviously..