This is cool! The inclusion of z kind of breaks this for my fellow Scandinavians though. Many of us don't really hear the difference between z and s, and even if we do we can't pronounce it properly.

The P/B distinction will be difficult for many people as well.

I believe this is one of the reasons that Toki Pona only has nine consonants (/p, t, k, s, m, n, l, j, w/) and five vowels (/a, e, i, o, u/).

Somme kind of error correcting would be nice too, perhaps?