throat, neck, pivot
吭 centers on the throat and neck as a passageway or narrow connecting point. The pivot sense extends this idea to a critical turning point or axis, like the neck is for the head.
吭 combines 口 (mouth) with 亢, which likely contributes the sound and the idea of a raised or prominent passage. The exact historical development is uncertain.
The mouth 口 beside 亢, which looks like a raised neck, points to the throat: the passage where sound comes out.
For コウ, imagine a coat collar so tight it presses on your throat: coat -> コウ, and you feel it right at your neck.
windpipe