This grammar of the Southern Unami language describes the phonology, the inflectional and derivational morphology, and some aspects of sentence and discourse structure. It does not include a formal treatment of syntax. The treatment of these topics in Delaware Verbal Morphology (Goddard 1979) has been entirely recast, and there are now sections on additional topics that substantially fill out the description of this often complex and idiosyncratic Algonquian language. The facts are presented discursively in small modules with examples. The phonemic transcription has been improved by distinguishing /sg/, /?g/, and /xg/ from /s/, /?/ and /x/ between vowels and after /n/. and by greater consistency in writing the contrast between /o/ and /u/, especially before /w/.The extensive phonological alternations are illustrated with examples of morphological contexts in which they characteristically appear. Static words, syllables, and segments (which have short phonemes inconsistent with the more usual phonological patterns) are treated. The inflection of nouns, pronouns, and verbs is described and illustrated with extensive paradigms, and particles, including enclitics, are treated. The processes of stem derivation are outlined for primary stems and for secondary stems (those derived from another stem). The types of reduplication are described. Several kinds of compounds are distinguished and illustrated. The basic facts of sentence structure are presented, including the function of absolute and objective transitive verbs (to mark distinctions of definiteness) and the use of oblique complements and adjuncts. Other features discussed include verbless sentences, participles (relative clauses), focus-fronting, discontinuous constituents, and gapping. Southern Unami is the heritage language of the Delaware Tribe of Indians (Bartlesville, Okla.) and the Delaware Nation of Western Oklahoma (Anadarko).