These varieties are very similar, but there is a significant difference between western varieties and eastern varieties, as revealed by recorded text testing done in the 1970s. Three dictionaries have been published for Upper Eastern Amuzgo in recent years. For Northern Amuzgo, no dictionary has yet been published, yet it too is very actively written. Lower Eastern Amuzgo and Southern Amuzgo are still not well documented, but work is underway. While the Mixtecan subdivision may indeed be the closest to Amuzgo within Oto-Manguean, earlier claims that Amuzgo is part of it have been contested.
Phonology
Consonants
The dialect presented in the following chart is Upper Eastern, as spoken in San Pedro Amuzgos as analyzed by Smith & Tapia. The following chart is based on Coronado Nazario et al. for the variety of Southern Amuzgo spoken in Huixtepec. The phonetic facts are very similar to that of other varieties, but the analysis is different.
Bilabial
Apico-dental
Apico-lamino-/ alveolar
Post-alveolar
Palatal
Velar
Glottal
Nasal
Plosive
Affricate
Fricative
Lateral approximant
Central approximant
Tap
In this analysis, the nasals and central approximants have distinctive allophones that depend on whether or not they precede a nasalized vowel. The approximant, which is before oral vowels or consonants in Huixtepec, is before nasalized vowels. The approximant is likewise nasalized before nasalized vowels, and elsewhere. The nasals are pronounced with an oral non-nasal release when they precede an oral vowel, and as such sound like in that context. Various other important details about the phonetics of Amuzgo are not presented in a simplified chart such as the one shown above.
Vowels
Amuzgo distinguishes seven vowels with respect to quality. In all the documented dialects, all but the two close vowels may be nasalized. Some descriptions claim that Amuzgo also has ballistic syllables, a possible type of supra-glottal phonation. Ballistic syllables are also a feature of the phonology of another Oto-Manguean branch, Chinantec.
Tones
Amuzgo has three basic tones: high, mid, and low. But it also has several combinations of tones on single syllables. The contour high-low is a common one. The following words are apparently distinguished only by tone in Huixtepec: /ha/ 'sour', /ha/ 'I', /ha/ 'we ', and /ha/ 'we '. See also the set: /ta/ 'hill', /ta/ 'thick', /ta/ ' father ', /ta/ 'slice'.
Morphology
Nouns are pluralized by a prefix. The common plural prefix is n-. Compare 'skin', 'skins'. Typically the consonant drops when the noun is pluralized: 'hand', 'hands', 'hands'. Animate nouns carry the classifier prefix. This classifier precedes the inflected noun, as in 'dog', 'dogs', 'dogs'.