Comment 11 for bug 654484

This bug also affects phoneticists, seing as the International Phonetic Alphabet – the universal means of notating language sounds – distinguishes clealy between [x], a velar fricative, and [χ], a uvular fricative. These are two different sounds that may distinguish one word from another, and therefore the distinction is a very important one.

Compare https://en.wikipedia.org/wiki/Voiceless_uvular_fricative and https://en.wikipedia.org/wiki/Voiceless_velar_fricative. It's absolutely necessary to fix this, or the Ubuntu font face cannot be used for describing the phonetics of languages that use a uvular stop, which quite a few do – see the first link.