As a member of the broader Athabaskan family, it has an extremely complex system of verbal morphology, often enabling entire sentences to be constructed with only a verb.

The fricated alveolar and postalveolar series are tend to be realized as slightly retroflex preceding /i/ and /e/, though these variants are in free variation with the unretroflexed realizations.

The formation of these is generally irregular, although certain patterns do exist, such as initial x, s, and ł becoming ɣ, z, and l when inflected (e.g. sàà > bí-zàà, 'his language') and a final V:h becoming Vʔ (e.g. t'ààh > bí-t'áʔ, 'his feather').

Some stem nouns, especially those referring to body parts, are inalienably possessed, i.e. they cannot occur without a possessor prefix (e.g. bí-dààh, 'his lips', but not *dààh).

Lastly, some can only take the indefinite prefix, effectively turning them into regular alienably possessed nouns starting with ʔí- (e.g. ʔí-dààh, 'enemy', but bí-ʔí-dààh, 'his enemy', not *bí-dààh).

Like those of most other Athabaskan languages, Plains Apache verbs are highly morphologically complex, exhibiting polypersonal agreement, rich aspect marking, and the characteristic Athabaskan classifier system (a set of four mandatory valence-changing prefixes found throughout the family).

Following is an example of a fully inflected verb with the ł- classifier prefix: ši-1SG.OBJ-go-NUM-∅-IPFV-∅-3SBJ-ł-CLF-bèèšboilši- go- ∅- ∅- ł- bèèš1SG.OBJ- NUM- IPFV- 3SBJ- CLF- boil'They two are boiling me'Like other Southern Athabaskan languages, Plains Apache has strongly head-final tendencies, with a predominant word order of subject-object-verb and postpositions rather than prepositions.

This is illustrated in the following example sentences: dèènáámankóówaterʔí-INDEF-ł-CLF-bééšboildèènáá kóó ʔí- ł- bééšman water INDEF- CLF- boil'The man boils water'séédirtmi-3SG-džǫ́ʔ-back-dą́ʔPPdà-ADV-yi-3OBJ-ɣí-PROG-ø-3SBJ-ø-CLF-nííłthrowséé mi- džǫ́ʔ- dą́ʔ dà- yi- ɣí- ø- ø- nííłdirt 3SG- back- PP ADV- 3OBJ- PROG- 3SBJ- CLF- throw'He threw dirt on his back'However, due to the morphological complexity of Plains Apache verb inflection, it is often possible for a sentence to consist of a single verb, e.g. da-NUM-di-THM-∅-IPFV-į̀į̀d-1DUPL.SBJ-∅-CLF-mą̀ą̀sgo to warda- di- ∅- į̀į̀d- ∅- mą̀ą̀sNUM- THM- IPFV- 1DUPL.SBJ- CLF- {go to war}'Each one of us is starting off to war' Unknown glossing abbreviation(s) (help);Noun phrases always contain only a noun, as Plains Apache has no determiners or adjectives; the equivalent of adjectival modification is achieved by the use of compound and nominalized nouns discussed above.