Namkung, Ju. Phonological Inventories of Tibeto-Burman Languages. 1996. hh:hld:Namkung:Tibeto-Burman
There are three tones only in the northern dialect - in the southern dialect, there are two, a "flat" tone and a "raised" tone.
/ia ua/ are accepted as diphthongs here because, unlike other diphthongs, they can be followed by final consonants other than the glottal stop.