Proto Krūvtah

Consonants
Marek's phonology for Kaufman

Vowels
Naturally, there's also a tone system. Every vowel has three tones: high [á], low [à] and neutral [a]. Labialization is triggered by the disappearance of a rounded vowel and by a consonant preceding any tonal rounded vowel (note [ɸ] and [ʋ] are the labialized versions of [f] and [ɰ]- though [ʋ] does occur independently, while [ɸ] does not.

Diphthongs include any vowel followed by any short mid-to-high vowel. The first vowel must be in a different place of articulation than the second.

Phonotactics
Legal onsets consist of C, C [+app/lateral], [+obstruent] [+pharyngeal], [+fricative] [+obstruent] ([+app/lateral]), [+obstruent] [+nasal +heterorganic] and nothing.

Nuclei only consist of vowels. Only one tonal vowel may exist per root.

Legal codas include C [+plosive], [-obstruent] C, and nothing.

Both approximants and fricatives agree in voice with a preceding plosive (note that ʕ serves as a voiced ħ and vice versa.) Outside of this rule, voiced fricatives do not exist- approximants, however, do distinguish voicing in independent positions.

Writing System
I'll let Kauf work out the orthography.