Avatime, also known as Afatime, Sideme, or Sia, is a Kwa language of the Avatime (self designation: Kedone (m.sg.)) people of eastern Ghana. The Avatime live primarily in the seven towns and villages of Amedzofe, Vane, Gbadzeme, Dzokpe, Biakpa, Dzogbefeme, and Fume.

Avatime is a tonal language with three tones, has vowel harmony, and has been claimed to have doubly articulated fricatives.

Avatime has nine vowels, /i ɪ e ɛ a ɔ o ʊ u/, though the vowels /ɪ ʊ/ have been overlooked in most descriptions of the language. It is not clear if the difference between /i e o u/ and /ɪ ɛ ɔ ʊ/ is one of advanced and retracted tongue root (laryngeal contraction), as in so many languages of Ghana, or of vowel height: different phonetic parameters support different analyses.

Avatime has vowel harmony. A root many not mix vowels of the relaxed /i e o u/ and contracted /ɪ ɛ a ɔ ʊ/ sets, and prefixes change vowels to harmonize with the vowels of the root. For example, the human singular gender prefix is /ɔ ~ o/, and the human plural is /a ~ e/: /o-ze/ "thief", /ɔ-ka/ "father"; /be-ze/ "thieves", /ba-ka/ "fathers"; also /o-bu/ "bee" but /ɔ-bʊ/ "god".

Vowels may be long or short. Records from 1910^{[clarification needed]} showed that all vowels could be nasalized, but that is disappearing, and few words with nasal vowels remained by the end of the century.

/ɸ/ is found in Ewe borrowings, as is /kʷ/, which can be seen to be distinct from /kw/ (which cannot be followed by another consonant) in the loanword /àkʷlɛ̄/ 'boat'.

The language has been claimed to have doubly articulated fricatives /x͡ɸ ɣ͡β/. However, as with similar claims for Swedish [ɧ], the labial articulation is not fricated, and these are actually labialized velars, /xʷ ɣʷ/. All velar fricatives are quite weak, and are more often [h ɦ hʷ ɦʷ].

The affricates vary between [t͡s], [d͡z] and [t͡ʃ], [d͡ʒ], which may be a generational difference.