Understanding the subtleties of filler words

Filler words serve the practical function of giving a moment to think of what to say next and also let the other person know that a pause is coming. The type of filler word used signals the length of the pause requested, with 'um' indicating a longer pause and 'uh' indicating a shorter pause. Additionally, filler words can be used to signal an abrupt change of subject or to proceed with delivering bad news in a less shocking manner.