All cultures arbitrate guidelines to regulate speaking time . During the conversation, it is important that we let others know that we want to talk. In some societies it is done with gestures: to silence the other by putting your hand in front of him is not frowned upon. For Westerners, however, gestures like these or raising the tone of voice to impose themselves are increasingly seen as aggressive. Little by little, they are being replaced by signals that imply that we are thinking and that, therefore, we are going to say something.
Both "umm" and "emm" are sounds emitted by a closed mouth about to open to speak: hence, they are interpreted as request to speak signals . Other scientists add that e is the most common vowel in many languages, or that u and e appear in not a few word principles.
