Complexities in the level tone systems of naish subgroup (sino-tibetan languages): Phonological and phonetic perspectives on qiansuo na

The level tone systems, widely spread in the Naish subgroup of Sino-Tibetan languages, are contrastive in comparison with the register tone systems as spotted in Sinitic languages. This paper reviews published evidences about the tonal systems in languages of the Naish subgroup of Sino-Tibetan languages and presents the results of a preliminary analysis on Qiansuo Na, a new field of documentation in the Na language studies. After a brief introduction on the background of Na, the second section aims at displaying the level tone systems revealed in several Naish subgroup languages and at summarizing the approaches applied so far by scholars to the tonal systems analysis. The case study section has its origin from the fact that the level tone systems are widespread in Naish languages. It reports the initial reconstruction of the tone systems in Qiansuo Na, highlighting in them a level tone system, categories of surface phonological tones, and complex underlying / lexical tones. The collected data about Qiansuo Na could contribute to a better understanding of Naish tone systems and to further comparative studies.