Here is an adaptation of the N'Ko Alphabet reversed to be used to write English. The Letter X and C have been omitted because of no existing equivalent, and the accented characters have not been added as of yet.

I could gladly try K on C and Ks on X, however, take these two examples: Circle, and Xinjiang. The first is pronounced "serkl", the latter "tsin-jee-yaang". The letter C represents either a hard S or a K sound, and when transliterating english it's relatively easy to represent those sounds accordingly, but, no other alphabet on Earth has a letter that both represents K and S, besides maybe some pronunciations of Thai or Lao or Burmese characters. A font simply replaces the existing characters, so it has no way of discerning the difference between a K and an S sounding C. Just like X, X can be pronounced "gz", "ks", "z", or "ts", and once again a font cant discern this. I really wish there was a replacement, as I dislike having to leave blank characters in my fonts (as you can see by my runic font), but I was forced to in this case and with the Tifinagh font as well.