Akkadian phonetics and phonology

Because Akkadian as a spoken language is extinct and no contemporary descriptions of the pronunciation are known, little can be said with certainty about the phonetics and phonology of Akkadian. Some conclusions can be made, however, due to the relationship to the other Semitic languages and variant spellings of Akkadian words.

Consonants
As far as can be told from the cuneiform orthography of Akkadian, several Proto-Semitic phonemes are lost in Akkadian. The Proto-Semitic glottal stop *ʾ, as well as the fricatives *ʿ, *h, *ḥ are lost as consonants, either by sound change or orthographically, but they gave rise to the vowel quality e not exhibited in Proto-Semitic. The interdental and the voiceless lateral fricatives (*ś, *ṣ́) merged with the sibilants as in Canaanite, leaving 19 consonantal phonemes.

The following table gives the consonant sounds distinguished in the Akkadian use of cuneiform, with the presumed pronunciation in IPA transcription according to Streck 2005. The parenthesised sign following is the transcription used in the literature, in the cases where that sign is different from the phonetic sign. This transcription has been suggested for all Semitic languages by the Deutsche Morgenländische Gesellschaft (DMG), and is therefore known as DMG-umschrift.

The status of as postalveolar and of  as fricatives is contested, for instance by Kogan and Dolgopolsky, due to attested assimilations of voiceless coronal affricates to. For example, when the possessive suffix is added to the root  ('word'), it is written  ('his word') even though  would be expected. What triggered the change from to  is unclear, especially since a shift of  to  does not occur in other contexts.

According to Patrick R. Bennett's "Comparative Semitic Linguistics: a manual", the *š was a voiceless alveolo-palatal. In the pronunciation of an alveolo-palatal, the tongue approximates the teeth more closely.

An alternative approach to the phonology of these consonants is to treat *s *ṣ as voiceless coronal affricates, *š as a voiceless coronal fricative and *z as a voiced coronal affricate or fricative. In this vein, an alternative transcription of *š is *s̠, with the macron below indicating a soft (lenis) articulation in Semitic transcription. The assimilation is then awat-su to, which is quite common across languages.

The following table shows Proto-Semitic phonemes and their correspondences among Akkadian, Arabic and Tiberian Hebrew:

Vowels
Additionally, most researchers presume the existence of back mid vowel, but the cuneiform writings give no good proof for this.

All consonants and vowels appear in long and short forms. Long consonants are represented in writing as double consonants, and long vowels are written with a macron (ā, ē, ī, ū). This distinction is phonemic, and is used in the grammar, for example iprusu ('that he decided') versus iprusū ('they decided').

Stress
Nothing is known of Akkadian stress. There are however certain points of reference, such as the rule of vowel syncope (see the next paragraph), and some forms in the cuneiform that might represent the stressing of certain vowels; however, attempts at identifying a rule for stress have so far been unsuccessful.

A rule of Akkadian phonology is that certain short (and probably unstressed) vowels are dropped. The rule is that the last vowel of a succession of syllables that end in a short vowel is dropped, for example the declinational root of the verbal adjective of a root PRS is PaRiS-. Thus the masculine singular nominative is PaRS-um (< *PaRiS-um) but the feminine singular nominative is PaRiStum (< *PaRiS-at-um). Additionally there is a general tendency of syncope of short vowels in the later stages of Akkadian.