Man... it happens with me all the time... (probably because i smoke everyday...) i already accepted it as a long term effect of smoking, so it doesnt bother me anymore. OK sometimes its hard to keep a conversation because of this, but as i never was a great "talker" i dont mind it very much.
And i dont know why it happens, or if the strain you smoke has anything to do with this... anyway, after one or two days without smoking this effect wears off, and you can talk "normally" again.