Riddles aren't like that, though. Most riddles are fairly easy things to figure out if you're logical. Answers aren't hidden, aren't varying, and are generally pretty equitable if you're a decently functioning human being. So it doesn't follow that using a variant in the way you commmunicate would be the answer. My_car etc. has already said that one can't cough while they're speaking, so why would they be able to stretch their words?

The more I think on it, the more I believe this is a joke or a bad riddle. Not because I can't deduce it, but because I can't see how it could be dedeuced.