Luganda phonology

A notable feature of Luganda phonology is its geminate consonants and distinctions between long and short vowels. Speakers generally consider consonantal gemination and vowel lengthening to be two manifestations of the same effect, which they call simply "doubling" or "stressing".

Luganda is also a tonal language; the change in the pitch of a syllable can change the meaning of a word. For example the word kabaka means 'king' if all three syllables are given the same pitch. If the first syllable is high then the meaning changes to 'the little one catches' (third person singular present tense Class VI ka- of -baka 'to catch'). This feature makes Luganda a difficult language for speakers of non-tonal languages to learn. A non-native speaker has to learn the variations of pitch by prolonged listening.

Vowels
All five vowels have two forms: long and short. The distinction is phonemic but can occur only in certain positions. After two consonants, the latter being a semivowel, all vowels are long. Before a prenasalised consonant, all vowels are long. Before a geminate, all vowels are short. The quality of a vowel is not affected by its length.

Consonants
The table below gives the consonant set of Luganda, grouping voiceless and voiced consonants together in a cell where appropriate, in that order.

Apart from, all these consonants can be geminated, even at the start of a word: bbiri 'two', kitto  'cold'. The approximants and  are geminated as  and : eggwanga  'country'; jjenje  'cricket'—from the roots -wanga  and -yenje  respectively, with the singular noun prefix e- that doubles the following consonant.

Apart from, and , all consonants can also be prenasalised—prefixed with a nasal stop. This consonant will be, , or  according to the place of articulation, and belongs to the same syllable as the consonant it precedes.

The liquid becomes  when geminated or prenasalised. For example ndaba 'I see' (from the root -laba with the subject prefix n-); eddagala  'leaf' (from the root -lagala with the singular noun prefix e-, which doubles the following consonant.

A consonant can't be both geminated and prenasalised. When morphological processes require this, the gemination is dropped and the syllable is inserted, which can then be prenasalised. For example when the prefix en- is aded to the adjective -ddugavu 'black' the result is enzirugavu.

The nasals, , and  can be syllabic at the start of a word: nkima  (or ) 'monkey', mpa  'I give', nnyinyonnyola  or  'I explain'. Note that this last example can be analysed in two ways, reflecting the fact that there's no distinction between prenasalisation and gemination when applied to nasal stops.

Tone
Luganda is a tonal language, with three tones: high, low and falling. A falling tone may occur only on the last syllable of a word. High and low tones may occur in any position.

Tones are carried on morae. In Luganda, a short vowel has one mora and a long vowel has two morae. A geminate or prenasalised consonant has one mora. (A vowel followed by a following prenasalised consonant has two morae including the one belonging to the prenasalised consonant.)

Prefixes often change the tones in a word. For example Baganda has LHHL, but adding the initial vowel a-  gives Abaganda  with L-LHLH. (Here, long vowels are transcribed double rather than with the length mark, to allow for tones to be written on each mora.)

Phonotactics
Syllables can take any of the following forms: where V = vowel, C = single consonant (including nasals and semivowels but excluding geminates), G = geminate consonant, N = nasal stop, S = semivowel
 * V (only as the first syllable of a word)
 * CV
 * GV
 * NCV
 * CSV
 * GSV
 * NCSV

These forms are subject to certain phonotactic restrictions:
 * Two vowels may not appear adjacent to one another. When morphological or grammatical rules cause two vowels to meet, the first vowel is elided or reduced to a semivowel and the second is lengthened if possible.
 * A vowel following a consonant–semivowel combination (except ) is always long. After a vowel can be either long or short.
 * A vowel followed by a nasal–plosive combination is always long.
 * A vowel followed by a geminate is always short. This rule takes precedence over all the above rules.
 * The velar plosives and  may not appear before the vowel  or the semivowel . In this position they become the corresponding postalveolar affricates  and  respectively.
 * The consonants, and ~ can't be geminated or prenasalised.
 * A consonant can't be both geminated and prenasalised.

The net effect of this is that all Luganda words follow the general pattern of alternating consonant clusters and vowels, beginning with either but always ending in a vowel: where V = vowel, X = consonant cluster, (V) = optional vowel
 * (V)XVXV...XV

This is reflected in the syllabification rule that words are always hyphenated after a vowel (when breaking a word over two lines). For example Emmotoka yange ezze 'My car has arrived' would be split into syllables as E‧mmo‧to‧ka ya‧nge e‧zze.

Variant pronunciations
The palatal plosives and  may be realised with some affrication—either as  and  or as postalveolars  and  respectively.

In speech, word-final vowels are often elided in these conditioning environments:
 * Word-final can be silent after, ,  or
 * Word-final can be silent after, ,  or

For example, ekiddugavu 'black' may be pronounced  or. Similarly lwaki 'why' may be pronounced,  or.

Long vowels before prenasalised fricatives (that is, before, , or ) may be nasalised, and the nasal is then often elided. Additionally, when not elided (for example phrase-initially), the usually becomes a labiodental in,. For example:
 * nfa 'I'm dying' is pronounced
 * musanvu 'seven' may be pronounced, ,  or
 * tonsaba 'don't ask me' may be pronounced,  or

The liquid has two allophones  and, conditioned by the preceding vowel. It is usually realised as a tap or flap after a close unrounded vowel (i.e. after, ,  or ), and as a lateral approximant  elsewhere. However, there's considerable variation in this, and using one allophone instead of the other causes no ambiguity. So lwaki 'why' may also be pronounced, ,  etc.

Alternative analysis
Treating the geminate and prenasalised consonants as separate phonemes yields the expanded consonant set below:

This simplifies the phonotactic rules so that all syllables are of one of three forms: where V = vowel, C = consonant (including geminate and prenasalised consonants), N = nasal stop, S = semivowel (i.e. either or ).
 * V (only as the first syllable of a word)
 * CV
 * CSV

Vowel length is then only distinctive before simple consonants (i.e. simple plosives, simple fricatives, simple nasals, approximants and liquids)—not before geminate or nasalised consonants or at the end of a word.