Sa or Saa language is an Austronesian language spoken in southern Pentecost Island, Vanuatu. It had an estimated 2,500 speakers in the year 2000.

Sa has numerous dialects, with no well-established names or boundaries. At a meeting in 2008, speakers recognised four main dialects, with sub-dialectal variation and mixing of dialects in some areas.

The two central dialects are relatively similar to one another and are generally understood by all Sa speakers. Most writing and research in Sa has been in one of these dialects:

• A western dialect ("Saa" with a long a) is spoken on the west coast around Panas, Wali, Panngi and Ranputor.
• An eastern dialect ("Sa" with a short a) is spoken in the south-east around Ranwas. A variant of this dialect with longer vowels in certain words is spoken at Poinkros in the far south, and is used in the Bible Society's recent Gospel translations.

There are also two outlying dialects, which are highly distinctive and difficult for speakers of other dialects to understand:

• A northern dialect ("F dialect"), characterised by the presence of an f sound, is spoken in the north of the Sa area, at St Henri (Fatsare) and by some at Ran'gusuksu. It has close links with neighbouring Ske language and with Doltes, the extinct dialect of Hotwata village.
• A southern dialect ("Ha"), notable for the widespread replacement of s with h, is spoken in Bay Martelli (Harop) and Londar, and has close links with the languages of neighbouring Ambrym island.

The distinctive speech of villages such as Bunlap, Bay Barrier (Ranon) and Wanur appears to comprise mixtures of neighbouring dialects.

People in southern Pentecost remember the existence of additional dialects that are now extinct.

The consonants of Sa include b, d, g, h, k, l, m, n, ng (as in English "singer"), p, r, s, t, and w. In most dialects there is also j (occasionally written "ts"), which is apparently an allophone of t found before the vowels i and u although speakers regard it separately. Most speakers also use labiovelar bw, mw and pw, although from some speakers of outlying dialects these are indistinguishable from normal b, m and p. In addition to these consonants, the northern dialect has a bilabial f. In this dialect s may be pronounced like English sh.

As a general rule, clusters of consonants do not occur within a syllable. Word roots may begin with a pair of consonants, but in speech the first of these consonants is usually either dropped or attached to the final syllable of the preceding word.

In addition to the five standard vowels (a, e, i, o and u), Sa is generally believed^{[by whom?]} to have additional mid-high vowels ê (intermediate between e and i) and ô (intermediate between o and u). Not all authors have recognised these extra vowels, but they have been accepted by local teachers of vernacular literacy and are used in the Bible Society's recent Gospel translations. Vowels are distinguished for length, with long vowels (aa, ee, etc.) often occurring where a consonant has historically been lost. Vowels can occur alone or in various combinations.

Stress is normally on the penultimate syllable of a word. However, syllables that end with a consonant or a long vowel take stress in precedence to other syllables.

Basic word order in Sa is subject–verb–object.