The languages belong to five different families: Zuni, Tanoan, Keresan, Uto-Aztecan, and Athabaskan. Zuni is a language isolate. Navajo is only a marginal member of the Sprachbund and does not share all its linguistic features. This is because the ancestors of the Navajo originate from the Athabaskan region, and as a result they were relatively late in arriving to the Southwest compared to their Puebloan neighbors. Languages in the Tanoan and Apachean families, and additionally Hopi, can be compared to relatives not affected by this particular region's areal features as a reference for changes due to contact. Tanoan consists of Taos, Picurís, Tewa, and Jemez. Keresan consists of Eastern Keres and Western Keres.
SOV word order have ; Tewa has ; Jemez has ; Keresan has . Hopi lacks ejectives completely. Navajo has.
Navajo may have acquired the stop /kʷ/ from Puebloan contact. Sherzer suggests that contact led to Acoma Keres sharing glottalized sonorants and glides with Navajo. Zuni may have obtained its partial glottalized set and aspirants via contact with Tanoan and Keresan, which both have fully integrated series of glottals. Other shared traits include Santa Clara acquiring retroflex sounds from Keresan and the Navajo acquiring /hʷ/ from Tanoan contact. Keresan may be the common source of glottalized nasals and semivowels in Navajo, and the development of /r/ in dialects of Tewa and Tiwa and possibly Hopi. Linguist Paul Kroskrity argues for diffused Apachean traits in Tewa, such as the passive marked by prefixes that are structured differently from those of other Tanoan languages. In these languages the verb is made intransitive by allowing an agent argument in the verb structure. This also includes patient subjects and cases where the subject must be animate, including raising animate objects to the place of inanimate subjects. Further, Navajo and Tewa are the only languages in this group to have a "recognizable anaphor as a relativizer" when forming relative clauses. Kroskrity also finds similarity in the Tewa possessive suffix -bí, which parallels the third personpossessive prefix bi- found in Apachean languages. This can be seen in the following example provided by Kroskrity:
This paralleling morpheme is also used in these languages' postpositional constructions. The reason for this diffusion has been attributed to trade networks and Apachean settlements near Pueblos in winter months.
Vowels
Sherzer suggests that the 2-2-1 vowel system found in Tanoan languages may be a result of contact with Zuni and Keresan language families. Sherzer states, "A 2-2-1 vowel system is a Pueblo-cintered regional areal trait. Its development in some Tanoan languages may be due to contact with Zuni and Keresan."
