Talking head and Utterer

Talking head noun - A talker on television who talks directly into the cameras and whose upper body is all that is shown on the screen.

Utterer and talking head are semantically related. In some cases you can use "Utterer" instead a noun phrase "Talking head".

Utterer noun - Someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous).

Talking head and utterer are semantically related. Sometimes you can replace phrase "Talking head" with "Utterer", this terms are similar.