I also wanted to add another aspect to this test:
The difference between wug-s (voiced fricative, sounds like z) and wug-s (unvoiced, sounds like s).

As an example:
Dogs (dog/z/)
Cats (cat/s/)

The same pluralization rule is applied to both words, but the actual sounds made are different depending on the voicing of the previous sound/letter. You can feel the 'voicing' (vibration) of different sounds by putting your hand on your throat while saying these words.

Also fun fact I have a tattoo of a wug :)