Also in this week's column:

• Whatever happened to the gay gene?
• What lies without: Life on the human body
• What's happened to whistling?

We know that "um", "er", and "ah" are called fillers and are used in conversations to keep the listener listening while the speaker searches for the next meaningful thing to say.

Although "um", "er", and "ah" are not meaningful sounds (phonemes), meaningful sounds (morphemes), words, and entire phrases can function as fillers. Examples are "right", "sure", "you know", and "I mean".

Tag questions are fillers in the form of a single word or a phrase asking agreement. Perhaps the most notable example of this these days is the English tag question "innit?" In actuality, this is a contraction of "isn't it?"

Many in the UK, mostly young people and particularly in London, are known to end nearly every sentence with "innit?" And the trend seems to be to drop altogether the intonation that indicates a sentence that asks a question (interrogative) and make it into a sentence that sets forth or provides an explanation (declarative).

Human language continually changes, innit.

Stephen Juan, Ph.D. is an anthropologist at the University of Sydney. Email your Odd Body questions to s.juan@edfac.usyd.edu.au