were reflexes of Proto-Poplocan. The San Miguel Huautla dialect occupies an intermediary position, sharing traits with both groups. The division between highland and lowland dialects corresponds to the political division between highland and lowland territories that existed from 1300 to 1519. During the period of Aztec dominance from 1456 to 1519, the Highland territory was ruled from Teotitlán del Camino and the lowland territory from Tuxtepec. The political division remains today. The distinction between highland and lowland dialects is supported by shared sound changes: in Lowland Mazatec dialects, Proto-Mazatecan merged with /*t/ before front vowels /*i/ and /*e/, and in the Highland dialects, merged with in position before /*k/. Lowland dialects Lowland dialects then split into Valley dialects and the dialect of San Miguel Huautla. The dialect of San Miguel Huautla underwent the same sound change of to before /*k/, which had already happened in the highland dialects, but in San Miguel Huautla, the shift happened after the merger of with /*t/ before /*i/ and /*e/. The Valley dialects underwent a change of /*n/ to in sequences with a /vowel-hn-a/ or /vowel-hn-u/. The Valley dialects then separated into Southern (Mazatlán and Jalapa) and Northern (Soyaltepec and Ixcatlán) valley dialects. The Southern dialects changed to /t/ before /*k/ (later changing *tk to /hk/ in Mazatlán and simplifying to /k/ in Jalapa), and the Northern dialects changed to before /*/a. The dialect of Ixcatlán then separated from the one of Soyaltepec by changing sequences of and to /tik/ and /tuk/, respectively. Highland dialects The Highland dialects split into Western and Eastern (Huautla de Jiménez and Jiotes) groups; in the Western dialects the sequence changed to /sk/, but the Eastern ones changed it to /hk/. The dialect of Huautla de Jiménez then changed sequences of to before short vowels, and the dialect of Santa Maria Jiotes merged the labialized velar stop to . Phonology Like many other Oto-Manguean languages, Mazatecan languages have complex phonologies characterized by complex tone systems and several uncommon phonation phenomena such as creaky voice, breathy voice and ballistic syllables. The following review of a Mazatecan phoneme inventory will be based on the description of the Jalapa de Díaz variety published by Silverman, Blankenship et al. (1995). Comparative Mazatec phonology The Mazatecan variety with the most thoroughly described phonology is that of Jalapa de Díaz, which has been described in two publications by Silverman, Blankenship, Kirk and Ladefoged (1994 and