The voiceless stops /t/ and /k/ are always aspirated.
/ʕ/, the voiced pharyngeal fricative, may have creaky voice.
/r/ is often pronounced with breathy voice and may be partially devoiced. Between vowels it may be a single tap.
Somali has five vowel articulations that all contrast murmured and harsh voice as well as vowel length. There is little change in vowel quality when the vowel is lengthened. Each vowel has a harmonic counterpart, and every vowel within a harmonic group (which notably can be larger than a word in Somalian) must harmonize with the other vowels. The Somali orthography, however, does not distinguish between the two harmonic variants of each vowel.
There are five diphthongs that also occur in front and back, long and short versions, except for /ɵi/, which does not appear to occur in the back series.
|Front series||Back series|
|Close front unrounded /
Near-close near-front unrounded
|Close-mid front unrounded /
Open-mid front unrounded
|Near-open front unrounded /
Open back unrounded
|Open-mid central rounded /
Open-mid back rounded
|Close central rounded /
Close back rounded
|First element is front||First element is back|
The tone system distinguishes both grammatical and lexical differences. Differences include numbers singular and plural (a grammatical distinction), and masculine and feminine genders (a grammatical and sometimes also lexical distinction). One example is inán ('girl') versus ínan ('boy'). This reflects a tonal pattern that codes grammatical gender, such as dameér ('female donkey') versus daméer ('male donkey').
The question of the tone system in Somali has been debated for decades. The modern consensus is as follows.
In Somali, the tone-bearing unit is the mora rather than the vowel of the syllable. A long vowel or a diphthong consists of two morae and can bear two tones. Each mora is defined as being of high or low tone. Only one high tone occurs per word and this must be on the final or penultimate mora. Particles do not have a high tone. (These include prepositions, clitic pronouns for subject and object, impersonal subject pronouns and focus markers.) There are therefore three possible "accentual patterns" in word roots.
Phonetically there are three tones on long vowels: high, low and falling:
- On a long vowel or diphthong, a sequence of high-low is realised as a falling tone.
- On a long vowel or diphthong, a sequence of low-high is realised as high-high. (Occasionally, it is a rising tone.)
Stress is connected with tone. The high tone has strong stress; the falling tone has less stress and the low tone has no stress.
When needed, the conventions for marking tone on written Somali are as follows:
Tones on long vowels are marked on the first vowel symbol.
The syllable structure of Somali is (C)V(C).
Root morphemes usually have a mono- or di-syllabic structure.
Clusters of two consonants do not occur word-initially or word-finally, i.e., they only occur at syllable boundaries. The following consonants can be geminate: /b/, /d/, /ɖ/, /ɡ/, /ɢ/, /m/, /n/, /r/ and /l/. The following cannot be geminate: /t/, /k/ and the fricatives.
Two vowels cannot occur together at syllable boundaries. Epenthetic consonants, e.g. [j] and [ʔ], are therefore inserted.
/dʒ does not occur syllable-final in native Somali words but it does in Arabic loans.
- The voiced stops (/b/, /d/, /ɡ/ and /ɖ/) are devoiced in word-initial and word-final position. Between two vowels they become fricatives.
- The voiceless stops /t/ and /k/ are realised as [d] and [ɡ] in syllable-final position.
- /m/ is realised as [n] in syllable-final position.
- Between vowels, /h/ is usually voiced to [ɦ].
- All vowels are nasalised before or after a nasal consonant.
When a vowel occurs in word-initial position, a glottal stop ([ʔ]) is inserted before it.
Trisyllabic roots with the form (C)VCVCV and a short second vowel elide this vowel to become (C)VCCV except if it would result in /t/ or /k/ occurring at the end of a syllable or being geminate.
Phonological changes occur at morpheme boundaries (sandhi) for specific grammatical morphemes. There may be assimilation or elision. One unusual change which can occur is /lt/ to [ʃ].
Coalescence also occurs. This is a kind of external sandhi in which words join, undergoing phonological processes such as elision. In Somali it is sometimes obligatory and sometimes it is dependent on the speech style.
Roots have front-back vowel harmony. There is also a process of vowel harmony in strings longer than a word, known as "harmonic groups".
- Gabbard, Kevin (2010). A Phonological Analysis of Somali and the Guttural Consonants (PDF) (BA Linguistics Honors Thesis).
- Saeed, John Ibrahim (1993). Somali Reference Grammar. Kensington, Maryland: Dunwoody Press. ISBN 978-0931745973.
- Saeed, John Ibrahim (1999). Somali. Amsterdam: John Benjamins, B.V. ISBN 90-272-3810-3.