The phonological system can only partly be reconstructed from the writing. During the time that Sumerian was an alive spoken language, most of the writing was logographic, thus offering no evidence for the pronunciation. The first syllabic resolutions of logograms are found from -1.850 on, i.e. at a time where Sumerian was no longer spoken. Pronunciation at that time would have been heavily influenced by Akkadian (the native language of the users). Thus, some phonology may be reconstructed for the stage at the middle of the 2nd millennium; however, it is methodologically illicit to posit this for the living Sumerian language of 500 or more years earlier. There is, anyhow, no other method (Falkenstein 1964:23).
The following phoneme system may be constructed from the writing. Since writing tends to reduce phonological distinctions, the actual phoneme system may have been larger; see below.
place manner
| labial | dental | alveo- palatal |
velar |
|---|---|---|---|---|
| stop voiceless | p | t | k | |
| voiced | b | d | g | |
| fric. voiceless | s | ʃ | x | |
| voiced | z | |||
| liquid | ɾ, l | r | ||
| nasal | m | n | ŋ | |
| glide | y | w | ||
| vowel | i | u | ||
| e | a |
The following symbols are often used in transliteration:
| phoneme | letter |
|---|---|
| x | ḫ |
| ʃ | š |
| ɾ | dr |
| ŋ | ĝ |
There may also have been glottal phonemes /ʔ/ and /h/; see below.
The vowel system is as follows:
/ a e i u /
There may have been a contrast between short and long vowels. This is, however, not consistently indicated in the cuneiform and almost never in the transliteration.
There may also have been nasal vowels and diphthongs (Falkenstein 1964:24).
The large number of apparent homophones may also indicate the existence of a tone system (Herrmann 1984, II:305).
The flap [ɾ] later merges with either /d/ or /r/ (that is why it is transliterated <dr>).
Adjacent vowels typically contract. Sometimes this does not occur. Partly to explain such cases, it has been assumed that there were yet other consonants, e.g. the glottal stop [ʔ], that do not appear in the writing.
In Ancient Sumerian, there are traces of vowel harmony.
The writing is insensitive to voicing in word-final obstruents, which may indicate a process of devoicing in the syllable coda syllable to the one familiar from Russian and German.