Maybe the cleanest vocoder on Audiotool? Tom Scott can still be a little hard to understand, or maybe I'm just American.

The vocals and carrier synth both are split into 9 bands, and an Envelope Follower on the vocal is applied to the carrier for each band. The band frequencies are spaced geometrically from 300Hz to 10000Hz.

Probably could do better with more bands, but this is already kinda much.

0:00 Normal speech

0:32 : Fade to vocoder with noise carrier

1:04 : Vocoder with synth chord carrier

2:08 : Coochie modulator