Zulu phonology

Vowels
and are pronounced  and  respectively when the following syllable contains an "i" or a "u", or when the vowel is word-final. They are and  otherwise.

Vowel length is not contrastive, but vowels are allophonically lengthened in the stressed (penultimate) syllable.

Consonants


The consonants marked with a diaeresis are depressor consonants, which affect the tone of their syllable. (See below.)

Click consonants
One of the most distinctive features of Zulu is the use of click consonants. This feature is shared with several other languages of Southern Africa, but is almost entirely confined to this region. There are three articulations of clicks in Zulu: Each articulation covers five click consonants, with differences such as being voiced, aspirated, or nasalised, for a total of 15. The and  series are depressor consonants, whereas  are not. An additional series occurs in Xhosa, where clicks are used more frequently than in Zulu.
 * c: dental (comparable to a sucking of teeth, as the sound one makes for 'tsk tsk')
 * q: alveolar (comparable to a bottle top 'pop')
 * x: lateral (comparable to a click one may do for a walking horse)

Tone
Like the great majority of other Bantu and African languages, Zulu is tonal. It is conventionally written without any indication of tone, although tone is distinctive in Zulu. For example, the words for priest and teacher are both spelled umfundisi, but they are pronounced with different tones.

Zulu syllables may have high, low, or falling tones. However, low tone is the default, and is over-ridden by neighbouring high tones, so it is common to describe low-tone syllables as having no inherent tone, with the two phonemic tones, high and falling, appearing on only certain syllables, rather like stress in English. The falling tone is actually a sequence of high–low, and only occurs on long vowels. Like other Bantu languages, Zulu has word tone, where tone patterns are largely independent of the number of syllables in a word. Zulu nouns have four principal tone patterns, while verbs have two.

Zulu is also known for having depressor consonants, which lower a high tone in their syllable. For example, the verbs ukuhlala "to live" and ukudlala "to play" both have a high tone on the prefix uku, which would normally cause the following syllable to have a high tone as well. However, the tone on the dla of ukudlala is low as a result of the depressor consonant dl. The depressor consonants are conventionally transcribed as breathy voiced, in this case or. However, phonetically it is the vowel which is breathy voiced,, and indeed vowels may be breathy voiced without a depressor consonant. The most salient difference between the slightly implosive consonants and the plosive depressor consonants  is this effect on tone.

Zulu has tonic assimilation, where high tones tend to spread to following toneless (low-tone) syllables. Specifically, a toneless syllable between a high-tone syllable and another tonic syllable assimilates to that high tone. That is, if the preceding syllable ends on a high tone, and the following syllable begins with a high tone (whether because it's high or high–low / falling), the intermediate toneless syllable is pronounced with a high tone as well. When the preceding syllable is high but the following is toneless, then the medial toneless syllable adopts a high-tone onset from the preceding syllable, resulting in a phonetic falling (high–low) tone.

In syllables with depressor consonants, however, high tones are realised as rising, and falling tones as rising-falling; in neither case do they reach as high as in non-depressed syllables. That is, depressor consonants add a low-tone onset to the inherent tone of the syllable; the possible tones on a syllable with a voiceless consonant like hla are, while the possible tones of a depressor-consonant syllable like dla are. If there is no inherent tone in the syllable, a depressor consonant blocks assimilation to a preceding high tone, keeping the tone low.

For example, the English word 'spoon' was borrowed into Zulu as isipunu. The initial 's' was reanalyzed as the singular prefix isi-, which has a high tone. The English stress on the 'oo' vowel was interpreted as a high tone, as normally happens with English loans. Thus the Zulu word isipunu is phonemically, and phonetically (high-tone spread to si, and low tone on the unmarked final syllable). The plural prefix for isi- nouns, however, is izi-, and Zulu z is a depressor consonant. Thus the plural 'spoons' is pronounced, with no tone assimilation. (In both cases, the high tone of pu is slightly lower than the tone of i, due to tonic downdrift. The penultimate syllable is also lengthened, as is normal in Zulu.)

Another example are the pair of words abantwana 'children' and amadada 'ducks'. is pronounced, with a long falling tone on the penult. D, however, is a depressor consonant, so is pronounced, with a long low tone on the penult.