Myself 09 said...
Are your thoughts racing when this happens? Are you saying something important, or are your emotions in play? Are you doing too many things at one time? Are you drinking enough water? Are you taking in enough air to finish your thoughts?
It could be anxiety. It could be just too much stimulation. It could be breath-related.
As your throat contracts, are you also breathing in, likely after the contraction?
I have always been a fast talker, and it isn't even anything emotional I am saying. I could be telling my husband what we are having for dinner and it will happen. I DO usually take a breath afterwards, though.