 Because of how they are incorporated into speech, such as specifically put to use at certain pauses in speech, attached as clitics onto other words, and prolonged for additional meaning, they have become a part of spontaneous speech that have meaning.What they argued was that "um" and "uh" are conventional English words and speakers plan for them, formulate them, and produce them just like any other vocabulary.Conversations as joint projects were where Clark explored vertical and horizontal transitions prompted by dialogue.