Eatough, Andrew. Proceeding from syllable inventory to phonemic inventory in the analysis of Liangshan Yi. 1997. sil16:37811
For the ʃʲ series, we have ɕ, although it'd technically be more consistent to treat these as ʆ as we do with ʃʲ series in Northwest Caucasian.
Eatough claims that Yi has no phonetic high vowels, and writes the fricated vowels as /i i̠ u u̠/. A native speaker of German judged _i o_ in [this Yi instructional video](https://www.youtube.com/watch?v
The high-mid tone has two main sources: ˧ > ˦ / _$˧, and ˩ > ˦ / ˧$_. These apply "in many, but not all, of the compound words where the phonological environment is met, as well as in certain syntactic contexts, such as across the boundary between an object and a verb."