Uhh... Umm...

The 'Uhs' and 'Ums' we naturally utter while speaking, or giving a speech, are generally considered to be a flaw, and a person who makes a lot of these pauses while giving a speech is generally considered weak, nervous, ignorant or sloppy.

But these pauses in natural human speech, called disfluencies, may not be a character flaw, but an organic feature of human speech, which is enhancing the listeners' understanding and comprehension.