Lisu phonology

The Lisu phonological inventory is as follows.

Vowels
and the fricative vowel are in complementary distribution:  is only found after palato-alveolars, though an alternate analysis is possible, with the palato-alveolars viewed as allophones of the palatals before  and. The distinction originates from proto-Lolo–Burmese consonant clusters of the type *kr or *kj, which elsewhere merge, but where Lisu normally develops, they remain distinct with the latter producing the type , the former the type. Inherited palatal affricates + also become.

is variable across dialects. It may be either endolabial or exolabial, central, or even merged with. The distinction between and  is marginal, and both are written $\langlee\rangle$ in pinyin.

Tones
Lisu has 6 tones: high, mid creaky , mid , low , rising , and low checked (that is, ). In some dialects the creaky tone is higher than mid tone, in others they are equal. The rising tone is infrequent, but common in baby talk (which has a stereotypical disyllabic low–rising pattern); both high and rising tone are uncommon after voiced consonants.

Consonants
and are in complementary distribution, with  before front vowels. is marginal, occurring in a few words before or. The subdialect Fraser first encountered also distinguishes a retroflex series,, but only before.

Medial glides appear before. These are with velars and  with bilabials and. The latter consonant (see rhinoglottophilia) has a non-nasal allophone in the imperative particle. is only distinctive before, and in some dialects is merged with.

In Southern Lisu, the velar plosives become alveopalatal before front vowels. The vowels and  trigger an offglide on preceding consonants, so  are pronounced.

The vowels do not occur initially—or, at least, in initial position they are pronounced. It has been argued that the initial vowels are phonetically, so initial consonants do not need to be posited in such cases (and marginal  can be removed from the inventory of native words), or that they are phonemically , with glottal stop (Bradley 2003).