Notes: The orthography used in this and related articles is that of South Africa, not Lesotho. For a discussion of the differences between the two see the notes on Sesotho orthography.
Like most other Niger–Congo languages, Sesotho is a tonal language, spoken with two basic tones, high (H) and low (L). The Sesotho grammatical tone system (unlike the lexical tone system used in Mandarin, for example) is rather complex and uses a large number of "sandhi" rules.
However, the Sesotho system is by no means the most complicated, nor even one of the more complicated. For example, there exist African grammatical tone languages with much more than just two tonemes, and the existence of breathy voiced consonants in the Nguni and other languages greatly complicates their tonology. (In Sesotho there is absolutely no interaction whatsoever between the tonemes and phones of the syllables.) There are also very few instances of "floating" tones, and fewer grammatical constructs indicated purely by a change in tone. (The most common instances of this are rule 1 of the plain copulative and the formation of many positive participial sub-mood clauses.) The rules are generally not very dramatic either, and there is generally a very strong tendency to preserve underlying high tones. (For example, in the Nguni languages the underlying high tone of verb stems, subjectival concords, the noun pre-prefix, and/or objectival concords often shifts several syllables to the right, to the antepenultimate or penultimate syllable.)
The tone of a syllable is carried by the vowel, or the nasal, if the nasal is syllabic.That is, the tone-bearing unit (TBU) is basically the syllable. In general, to include languages with long vowels, one may say that the TBU of Bantu languages is the mora, and indeed, when dealing with stressed syllables, many descriptions of Sesotho tonology treat the TBU as the mora (that is, a long stressed syllable is analysed as two moras with different tones), but this is really unnecessary. The tone carried by syllabic (and, in Northern Sotho and Setswana, syllabic is left over from the elided vowel.
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Tone types
Underlyingly, each syllable of every morpheme may be described as having one of two tone types:One could just as easily say that there are three underlying tone types—high (H [ ¯ ]), low (L [ _ ]), and null (ø)—and indeed many authors and researchers do. The truth is revealed by noting that all tonal rules work by only manipulating high tones, thus each syllable may be either attached to a high tone (H), or not attached at all (ø). A three tone model would at least require a rule that works exclusively on the L tones. high (H [ ¯ ]) and null (ø). On the surface, all remaining null tones default to low (the LTA rule below) and the language is therefore spoken with two contrasting tonemes (H and L).
A classic example of a nasal carrying a tone:
To form a locative from a noun, one of the possible procedures involves simply suffixing a low tone to the noun. To form the locative meaning "on the grass" one suffixes -ng to the word jwang‡ [ _ ¯ ], giving jwanng‡ [ _ ¯ _ ] , with the two last syllabic nasals having contrasting tones.
Names, being nouns, frequently have a tonal pattern distinct from the noun:
The Sesotho word for "mother" is mme‡ [ _ ¯ ], but a child would call their own mother mme‡ [ ¯ _ ], using it as a first name. Also, ntate‡ [ _ _ ¯ ] means "father", while ntate‡ [ _ ¯ ¯ ] might be used by a small child to address their father.
Allotones
In speech, the two surface tonemes may be pronounced as one of several allotones due to the influence of surrounding tones and the length of the syllable. These changes naturally occur due to the way the language is spoken, including the effect of the penultimate lengthening, but ultimately each syllable of every morpheme may be completely described as having only high and low tones.Doke & Vilakazi cites nine pitch levels (not counting contours) for isiZulu, while admitting that they may have overlooked some factors which could have superficially increased the actual number. Subsequent work on isiZulu tonology and depressor (breathy voiced) consonants suggests that the language, like Sesotho, may be fully described with only three or two basic tonemes.
In this and related articles, the tonemes of a word are delimited with square brackets and the specific (approximate) spoken allotones are between curly braces.
lepata euphemism; tonemes: [ _ ¯ _ ] (L—H — L), allotones: { _ _ } (low—high-falling—low)
+ Tonemes and allotonesToneme Allotone Where found ExampleH [ ¯ ] extra-high { ¯ } After another H, not penult moririnyana ('small hair') { _ ¯ ¯ ﹨ _ } high { ¯ } In the bodies of words ho lekola ('to investigate') { _ _ } mid { – } Finally in a phrase Mopedi Mopedi ('person') { _ ﹨ } high-falling { } Penultimate syllable of phrase before L mmuo ('dialect') { _ _ } high-mid { ﹨ } Penult before H mosadi ('woman') { _ ﹨ – }L [ _ ] extra-low { _ } Finally after another L temo ('agriculture') { ﹨ _ } low { _ } Noun class prefixes, in the bodies of words, and finally after H ho seba ('to perform mischief') { ﹨ _ } low-falling { ﹨ } Penultimate tweba ('mouse') { ﹨ _ }
Thus in all there are, at least in this analysis, eight allotonesThe number may increase or decrease depending on how one counts etc, but there are only two contrastive tonemes in the language. The enumeration may be further complicated by considering the effects of downdrift and downstep. { ¯ ¯ – _ _ ﹨ ﹨ }.
Most of these allotones only appear on the final word in the phrase in moderately slow or emphasised speech. When not phrase-final, the mid, high-falling, high-mid, low-falling, and extra-low allotones are normally not heard. Bear in mind that the falling tones only occur on lengthened syllables, and if a word has irregular stress then the falling tones will not appear on the penult (for example, the second form of the first demonstrative pronoun has tonemic pattern [ ¯ ¯ ] which is pronounced { ¯ } due to the stressed final syllable).
There are no rising tones. For example, [ _ ¯ ] (where the L is penultimate) is pronounced { ﹨ – } though one might have expected *{ ／ ¯ }. This is a general trend among almost all Bantu languages with (contrastive or stressed) lengthened vowels, though languages with depressor consonants do have audible upward "swoops" on depressing syllable onsets which may be interpreted as rising allotones.
There are several cases of seemingly tonemic instances of some of these allotones. As expected, some ideophones and radical interjectives have strange tones, but relative concord has an irregular extra-high tone (except when used to form demonstrative pronouns). The difference in relative pitch between the high tone and its extra-high allotone is less than that between the low and high tones.
Tone usage
The purpose of the tones can fall into at least one of the following categories:
Characteristic tone
Each complete Sesotho word has an inherent tone for its syllables, which, although not essential to forming correct speech, will betray a foreign accent:
motho‡ [ _ _ ] ('human being') ntja‡ [ _ ¯ ] ('dog') Mosotho‡ [ _ ¯ _ ] ('singular of Basotho') lerata‡ [ _ _ ¯ ] ('noise')
Various factors mean that the tones of a word may change, but the characteristic tone in a Sesotho word is found when the word is the last in a question sentence not employing the interrogative adverb na?. In this situation, downdrift is greatly attenuated, the penultimate syllable of the sentence is short (although the vowel of the last syllable may completely cut), and the tone of the last word is largely preserved (though a final H tone may fall to L).
O batla ho eba setsebi‡ { _ _ } ('you want to be a scientist') Na o batla ho eba setsebi?‡ { _ _ } ('do you want to be a scientist?') O batla ho eba setsebi?‡ { _ ¯ _ } ('do you want to be a scientist?')
Distinguishing/semantic tone
The most important property of tonal languages which distinguishes them from languages that merely use pitch as part of intonation (such as English) is the existence of numerous tonal minimal pairs. Often, a few words may be composed of exactly the same syllables/phonemes, yet have different characteristic tones (the example H verbs have low final tone due to the Finality Restriction):
ho aka‡ [ _ ¯ _ ] ('to kiss') ho aka‡ [ _ _ _ ] ('to tell lies')
jwang‡ [ _ ¯ ] ('grass') jwang‡ [ ¯ _ ] ('how?')
ho tena‡ [ _ ¯ _ ] ('to wear') ho tena‡ [ _ _ _ ] ('to disgust')
There are, however, several basic homophones pronounced with exactly the same tonal patterns. In these cases only the context may be used to distinguish between the different meanings.
-laola L verb (i) 'rule'; (ii) 'divine' -rola H verb (i) 'to forge metal', 'to hammer'; (ii) 'to undress' mohlwa [ _ ¯ ] (i) 'termite'; (ii) 'lawn grass (of the graminaceae family)'
There are instances of words being changed either through inflexion or derivation and as a result ending up sounding exactly like other words.
hlolo [ _ _ ] (i) 'hare', (ii) 'creation' (from the L verb -hlola)
Grammatical tone
It regularly occurs that two otherwise similar sounding phrases may have two very different meanings mainly due to a difference in tone of one or more words or concords.
Ke ngwana wa hao‡ [ _ _ ¯ ¯ ¯ _ ] ('I am your child') Ke ngwana wa hao‡ [ ¯ _ ¯ ¯ ¯ _ ] ('he/she/it is your child') O mobe‡ [ _ _ ¯ ] ('you are ugly') O mobe‡ [ ¯ _ ¯ ] ('he/she is ugly') Ke batlana le bona‡ [ _ _ _ _ ¯ _ _ ] ('I am looking for them' present indicative mood) Ke batlana le bona‡ [ ¯ ¯ _ _ ¯ _ _ ] ('as I was looking for them' participial sub-mood; this is not a complete sentence but part of a longer sentence)
Note that when grammatical tone is used the tone of the significant word may influence the relative pitch of the rest of the phrase, although the tones of other words tend to remain intact.
Downdrift
Downdrift, where the absolute pitch (not tones) of the speaker's voice is gradually decreased as the sentence continues (often resulting in initial low tones being pronounced at a higher pitch than final high tones), is a feature during natural speech. Basically, a high tone immediately following a low tone is pronounced at a slightly lower frequency than a previous high tone.
Additionally, a slightly more dramatic lowering of pitch (a downstep) may occur between certain syllables. In Sesotho, the downstep (indicated with a !) naturally occurs between words (being less noticeable if the first word has no low tones) though there is at least one instances (in rule 1 of the plain copulative) where the lack of downstep (as well as other tonal factors) changes the utterance's meaning. In the following example, a grave accent (à) indicates a low tone and an acute accent (á) indicates a high tone.
Kè bàtlà
!ó ló mò shébà
!hòrè
!ó ìlé
!káè
This downdrift is greatly attenuated when the sentence is a question not using the interrogative adverb na?.
Verb tone
Sesotho verb stems fall into two categories: H stems and L stems. The difference lies in the "underlying tone" of the stem's first syllable (or the stem's "basic tone") being either high or null. When used with an object in the indicative remote future tense (the simple -tla- tense) the verb's stem is monotonous (all syllables high toned or all low toned) with the underlying tone of the first syllable spread to all the following syllables.
Nouns derived from the verb stem are fossilised with the tones of the simple class 15 infinitive as appears in medial positions without a subject or object. The procedure for creating this tonal pattern is intricate and involves several tonal rules.
These factors may also apply in normal verbal conjugations. Adding a verbal suffix (through derivation, not inflexion) creates a new verb stem which falls in the same tone category as the original, and is subject to the same rules.