Sounds such as 'um' and 'uh' are common in speech when the speaker needs to prolong a sentence or otherwise control the rhythm of the sentence. I also hear these sounds used to convey indifference or indecision. Sometimes words, rather than sounds, are used in this capacity too, eg. 'so', 'like', 'well'.
The exact sound is usually fairly consistent within languages, but differs between languages, eg. in French the sound usually starts with a 'b' whereas in English they typically start vowels.
Do these words have a linguistic term?
