Tone is the use of pitch in language to distinguish lexical or grammatical meaning—that is, to distinguish or inflect words. All languages use pitch to express emotional and other paralinguistic information, and to convey emphasis, contrast, and other such features in what is called intonation, but not all languages use tones to distinguish words or their inflections, analogously to consonants and vowels. Such tonal phonemes are sometimes called tonemes.
In the most widely-spoken tonal language, Chinese, tones are distinguished by their shape (contour), most syllables carry their own tone, and many words are differentiated solely by tone. Moreover, tone plays little role in modern Chinese grammar, though the tones descend from features in Old Chinese that did have morphological significance. In many tonal African languages, such as most Bantu languages, however, tones are distinguished by their relative level, words are longer, there are fewer minimal tone pairs, and a single tone may be carried by the entire word, rather than a different tone on each syllable. Often grammatical information, such as past versus present, "I" versus "you", or positive versus negative, is conveyed solely by tone.
Many languages use tone in a more limited way. Somali, for example, may only have one high tone per word. In Japanese, less than half of the words have drop in pitch; words contrast according to which syllable this drop follows. Such minimal systems are sometimes called pitch accent, since they are reminiscent of stress accent languages which typically allow one principal stressed syllable per word. However, there is debate over the definition of pitch accent, and whether a coherent definition is even possible.
Most languages of sub-Saharan Africa are tonal, though notably excepting Swahili in the East, and Wolof and Fulani in the West. The Chadic, Omotic, and to some extent Cushitic branches of Afroasiatic are tonal—the Omotic languages heavily so—though their sister families of Semitic, Berber, and Egyptian are not.
There are numerous tonal languages in East Asia, including all the Chinese languages (though some such as Shanghainese are only marginally tonal), Vietnamese, Thai, Lao, and to a lesser extent Burmese, Korean, and Japanese (these simple systems are sometimes called 'register' (Burmese) or 'pitch accent' (Korean, Japanese)), but not Mongolian, Khmer, or Malay. Of the Tibetan languages, Central Tibetan (including the dialect of the capital Lhasa) and Amdo Tibetan are tonal, while Khams Tibetan and Ladakhi are not.
Some of the native languages of North and South America are tonal, notably many of the Na-Dené languages of Alaska and the American Southwest (including Navajo), and especially the Oto-Manguean languages of Mexico. Among the Mayan languages, which are mostly non-tonal, Yucatec (with the largest number of speakers), Uspantek, and one dialect of Tzotzil have developed tones.
In Europe, Norwegian, Swedish, Latvian, Lithuanian, Serbian, Croatian, some dialects of Slovene, and Limburgish have simple tone systems generally characterized as pitch accent. Other Indo-European tonal languages, spoken in the Indian subcontinent, are Punjabi, Lahanda, Rabinian and Western Pahari.
Languages that are tonal include:
The vast majority of Austronesian languages are non-tonal, but a small number have developed tone. No tonal language has been reported from Australia. With other languages we simply don't know. For example, the Ket language has been described as having up to eight tones by some investigators, as having four tones by others, but by some as having no tone at all. In cases such as these, the classification of a language as tonal may depend on the researcher's interpretation of what tone is. For instance, the Burmese language has phonetic tone, but each of its three tones is accompanied by a distinctive phonation (creaky, murmured or plain vowels). It could be argued either that the tone is incidental to the phonation, in which case Burmese would not be phonemically tonal, or that the phonation is incidental to the tone, in which case it would be considered tonal. Something similar appears to be the case with Ket.
A famous example of tone in Ancient Greek comes from Aristophanes' Frogs, where (l. 304) Aristophanes mentions an instance at a performance of Euripides' play Orestes, where an actor pronounced galḗn' horō "I see calm waters" with so much empathy that it came out galên horō "I see a frog"
Most languages use pitch as intonation to convey prosody and pragmatics, but this does not make them tonal languages. In tonal languages, each syllable has an inherent pitch contour, and thus minimal pairs exist between syllables with the same segmental features but different tones.
Here is a minimal tone set from Mandarin Chinese, which has five tones, here transcribed by diacritics over the vowels:
These tones combine with a syllable such as "ma" to produce different words. A minimal set based on "ma" are, in pinyin transcription,
These may be combined into the rather contrived sentence,
A well-known tongue-twister in the Thai language is:
Tones can interact in complex ways through a process known as tone sandhi. (See below: #Tone terracing and tone sandhi)
Tone systems fall into two broad patterns: Register tone systems and contour tone systems.
Most Chinese languages use contour tone systems, where the distinguishing feature of the tones are their shifts in pitch (that is, the pitch is a contour), such as rising, falling, dipping, or level. Most Bantu languages, on the other hand, have register tone systems, where the distinguishing feature is the relative difference between the pitches, such as high, mid, or low, rather than their shapes. In many register tone systems there is a default tone, usually low in a two-tone system or mid in a three-tone system, that is more common and less salient than other tones. There are also languages that combine register and contour tones, such as many Kru languages, where nouns are distinguished by contour tones and verbs by register. Others, such as Yoruba, have phonetic contours, but these can easily be analysed as sequences of register tones, with for example sequences of high–low /áà/ becoming falling [âː], and sequences of low–high /àá/ becoming rising [ǎː].
The term "register", when not used in the phrase "register tone", commonly indicates vowel phonation combined with tone in a single phonological system. Burmese, for example, is a register language, where differences in pitch are so intertwined with vowel phonation that neither can be considered without the other.
Tones are realized as pitch only in a relative sense. 'High tone' and 'low tone' are only meaningful relative to the speaker's vocal range and in comparing one syllable to the next, rather than as a contrast of absolute pitch such as one finds in music. As a result, when one combines tone with sentence prosody, the absolute pitch of a high tone at the end of a prosodic unit may be lower than that of a low tone at the beginning of the unit, because of the universal tendency (in both tonal and non-tonal languages) for pitch to decrease with time in a process called downdrift.
Tones may affect each other just as consonants and vowels do. In many register-tone languages, low tones may cause a downstep in following high or mid tones; the effect is such that even while the low tones remain at the lower end of the speaker's vocal range (which is itself descending due to downdrift), the high tones drop incrementally like steps in a stairway or terraced rice fields, until finally the tones merge and the system has to be reset. This effect is called tone terracing.
Sometimes a tone may remain as the sole realization of a grammatical particle after the original consonant and vowel disappear, so it can only be heard by its effect on other tones. It may cause downstep, or it may combine with other tones to form contours. These are called floating tones.
In many contour-tone languages, one tone may affect the shape of an adjacent tone. The affected tone may become something new, a tone that only occurs in such situations, or it may be changed into a different existing tone. This is called tone sandhi. In Mandarin Chinese, for example, a dipping tone between two other tones is reduced to a simple low tone, which otherwise does not occur in Mandarin, whereas if two dipping tones occur in a row, the first becomes a rising tone, indistinguishable from other rising tones in the language. For example, the words 很[xɤn˨˩˦] 'very' and 好[xaʊ˨˩˦] 'good' produce the phrase 很好[xɤn˧˥ xaʊ˨˩˦] 'very good'.
Another difference between tonal languages is whether the tones apply independently to each syllable or to the word as a whole. In Cantonese, Thai, and to some extent the Kru languages, each syllable may have any tone, whereas in Shanghainese, the Scandinavian languages, and many Bantu languages, the contour of each tone operates at the word level. That is, a trisyllabic word in a three-tone syllable-tone language has many more tonal possibilities (3×3×3=27) than a monosyllabic word (3), but there is no such difference in a word-tone language. For example, Shanghainese has two contrastive tones no matter how many syllables are in a word. Many languages described as having pitch accent are word-tone languages.
Tone sandhi is an intermediate situation, as tones are carried by individual syllables, but affect each other so that they are not independent of each other. For example, a number of Mandarin suffixes and grammatical particles have what is called (when describing Mandarin) a "neutral" tone, which has no independent existence. If a syllable with a neutral tone is added to a syllable with a full tone, the pitch contour of the resulting word is entirely determined by that other syllable:
|Tone in isolation||Tone pattern with
added 'neutral tone'
After high level and high rising tones, the neutral syllable has an independent pitch that looks like a mid register tone – the default tone in most register-tone languages. However, after a falling tone it takes on a low pitch; the contour tone remains on the first syllable, but the pitch of the second syllable matches where the contour leaves off. And after a low-dipping tone, the contour spreads to the second syllable: The contour remains the same (˨˩˦) whether the word has one syllable or two. In other words, the tone is now the property of the word, not the syllable. Shanghainese has taken this pattern to its extreme, as the pitches of all syllables are determined by the tone before them, so that only the tone of the initial syllable of a word is distinctive.
Languages with simple tone systems or pitch accent may have one or two syllables specified for tone, with the rest of the word taking a default tone. Such languages differ in which tone is marked and which is the default. In Navajo, for example, syllables have a low tone by default, while marked syllables have high tone. In the related language Sekani, however, the default is high tone, and marked syllables have low tone. There are parallels with stress: English stressed syllables have a higher pitch than unstressed syllables, whereas in Russian, stressed syllables have a lower pitch.
In East Asia, tone is typically lexical. This is characteristic of heavily tonal languages such as Chinese, Vietnamese, Thai, and Hmong. That is, tone is used to distinguish words which would otherwise be homonyms, rather than in the grammar, though some Yue Chinese dialects have minimal grammatical use of tone. However, in many African languages, especially in the Niger-Congo family, tone is crucial to the grammar, with relatively little lexical use. In the Kru languages, a combination of these patterns is found: nouns tend to have complex tone systems reminiscent of East Asia, but are not much affected by grammatical inflections, whereas verbs tend to have simple tone systems of the type more typical of Africa, which are inflected to indicate tense and mood, person, and polarity, so that tone may be the only distinguishing feature between 'you went' and 'I won't go'. In colloquial Yoruba, especially when spoken quickly, vowels may assimilate to each other, and consonants elide, so that much of the lexical and grammatical information is carried by tone. In languages of West Africa such as Yoruba, people may even communicate with so-called "talking drums", which are modulated to imitate the tones of the language, or by whistling the tones of speech.
There are three main approaches to notating tones in phonetic descriptions of a language.
In African linguistics (as well as in many African orthographies), usually a set of accent marks is used to mark tone. The most common phonetic set (which is also included in the International Phonetic Alphabet) is found below:
Several variations are found. In many three tone languages, it is common to mark High and Low tone as indicated above, but to omit marking of the Mid tone, e.g., má (High), ma (Mid), mà (Low). Similarly, in some two tone languages, only one tone is marked explicitly.
With more complex tonal systems, such as in the Kru and Omotic languages, it is usual to indicate tone with numbers, with 1 for HIGH and 4 or 5 for LOW in Kru, but 1 for LOW and 5 for HIGH in Omotic. Contour tones are then indicated 14, 21, etc.
In the Chinese tradition, numerals are assigned to various tones. For instance, Standard Mandarin has four lexically contrastive tones, and the numerals 1, 2, 3, and 4 are assigned to four tones. Syllables can sometimes be toneless and are described as having a neutral tone, typically indicated by omitting tone markings. Chinese dialects are traditionally described in terms of four tonal categories ping 'level', shang 'rising', qu 'exiting', ru 'entering'. Depending on the dialect, each of these categories may then be divided into two tones, typically called yin and yang. Syllables carrying the ru tones are closed by voiceless stops in all Chinese dialects, so that ru is not a tonal category in the sense used by Western linguistics, but rather a category of syllable structures. Chinese phonologists perceived these checked syllables as having concomitant short tones, justifying them as a tonal category. During the period of Middle Chinese, when the tonal categories were established, the shang and qu tones also had characteristic final obstruents with concomitant tonic differences, whereas syllables bearing the ping tone ended in a simple sonorant. An alternate to using the Chinese category names is to assign to each category a numeral ranging from 1–8, or sometimes higher for dialects with additional tone splits. It should be noted that syllables belonging to the same tone category differ drastically in actual phonetic tone across the Chinese dialects. For example, the yin ping tone is a high level tone in Beijing Mandarin, but a low level tone in Tianjin Mandarin.
More iconic systems are to use tone numbers, or an equivalent set of graphic pictograms known as 'Chao tone letters'. These divide the pitch into five levels, with the lowest being assigned the value 1, and the highest the value 5. (This is the opposite of equivalent systems in Africa and the Americas.) The variation in pitch of a tone contour is notated as a string of two or three numbers. For instance, the four Mandarin tones are transcribed as follows (note that the tone letters will not display properly unless you have a compatible font installed):
|High tone||55||˥˥||(Tone 1)|
|Mid rising tone||35||˧˥||(Tone 2)|
|Low dipping tone||214||˨˩˦||(Tone 3)|
|High falling tone||51||˥˩||(Tone 4)|
A mid-level tone would be indicated by /33/, a low level tone /11/, etc.
Standard IPA notation is also sometimes seen for Chinese. One reason it is not more widespread is that only two contour tones, rising /ɔ̌/ and falling /ɔ̂/, are widely supported by IPA fonts, while several Chinese languages have more than one rising or falling tone. One common work-around is to retain standard IPA /ɔ̌/ and /ɔ̂/ for high-rising (/35/) and high-falling (/53/) tones, and to use the subscript diacritics /ɔ̗/ and /ɔ̖/ for low-rising (/13/) and low-falling (/31/) tones.
The Thai language has five tones: high, mid, low, rising and falling. The Thai written script is an alphasyllabary which specifies the tone unambiguously. Tone is indicated by an interaction of the initial consonant of a syllable, the vowel, the final consonant (if present), and sometimes a tone mark. A particular tone mark may denote different tones depending on the initial consonant.
Vietnamese uses the Latin alphabet, and the 6 tones are marked by diacritics above or below a certain vowel of each syllable. In many words that end in diphthongs, however, exactly which vowel is marked is still debatable. Notation for Vietnamese tones are as follows:
|ngang||mid level, ˧||not marked||a|
|huyền||low falling, ˨˩||grave accent||à|
|sắc||high rising, ˧˥||acute accent||á|
|ngã||creaky rising, ˧ˀ˥||tilde||ã|
|nặng||creaky falling, ˧ˀ˨||dot below||ạ|
The Latin-based Hmong and Iu Mien alphabets use full letters for tones. In Hmong, one of the eight tones (the ˧ tone) is left unwritten, while the other seven are indicated by the letters b, m, d, j, v, s, g at the end of the syllable. Since Hmong has no phonemic syllable-final consonants, there is no ambiguity. This system enables Hmong speakers to type their language with an ordinary Latin-letter typewriter without having to resort to diacritics. In the Iu Mien, the letters v, c, h, x, z indicate tones but, unlike Hmong, it also has final consonants written before the tone.
Several North American languages have tone, one of which is Oklahoma Cherokee, said to be the most musical of the Iroquoian languages. Cherokee has six tones (1 low, 2 medium, 3 high, 4 very high, 23 rising and 32 falling).
In Mesoamericanist linguistics, /1/ stands for High tone and /5/ stands for Low tone, except in Oto-Manguean languages, where /1/ may be Low tone and /3/ High tone. It is also common to see acute accents for high tone and grave accents for low tone and combinations of these for contour tones. Several popular orthographies use ‹j› or ‹h› after a vowel to indicate low tone.
Southern Athabascan languages that include the Navajo and Apache languages are tonal, and are analyzed as having 2 tones, high and low. One variety of Hopi has developed tone, as has the Cheyenne language.
The Mesoamerican language stock called Oto-Manguean is notoriously tonal and is the largest language family in Mesoamerica, containing languages including Zapotec, Mixtec, and Otomí, some of which have as many as 8 different tones (Chinantec,) and others only two (Matlatzinca and Chichimeca Jonaz). Other languages in Mesoamerica that have tones are Huichol, Yukatek Maya, Tzotzil Maya of San Bartolo and Uspantec Maya (Quiché of Uspantán), and one variety of Huave.
A number of languages of South America are tonal. For example, the Pirahã language has three tones. The Ticuna language isolate is exceptional for having five level tones (the only other languages to have such a system are the Trique language and the Usila dialect of Chinantec (both Oto-Manguean languages of Mexico).
Both Swedish and Norwegian have simple word tone systems, often called pitch accent, that only appears in words of two or more syllables. This differentiates some two-syllable words depending on their morphological structure. The two word tones are usually called accent 1 and accent 2 (or acute accent and grave accent), respectively. Limburgish is similar. For further explanation and examples, see the Swedish, Norwegian, and Limburgish language articles.
In practical alphabetic orthographies, a number of approaches are used. Diacritics are common, as in pinyin, though these tend to be omitted. Thai uses a combination of redundant consonants and diacritics. Tone letters may also be used, for example in Hmong RPA and several minority languages in China. Or tone may simply be ignored. This is possible even for highly tonal languages: for example, the Chinese navy has successfully used toneless pinyin in government telegraph communications for decades, and likewise Chinese reporters abroad may file their stories in toneless pinyin. Dungan, a variety of Mandarin spoken in Central Asia, has had a written literature since 1927 in orthographies that do not indicate tone since. Ndjuka, where tone is less important, ignores tone except for a negative marker. However, the reverse is also true: In the Congo, there have been complaints from readers that newspapers written in orthographies without tone marking are insufficiently legible.
Languages may distinguish up to five levels of pitch, though the Chori language of Nigeria is described as distinguishing six surface tone registers. Since tone contours may involve up to two shifts in pitch, there are theoretically 5*5*5 = 125 distinct tones for a language with 5 registers. However, the most that are actually used in a language is a tenth of that number.
Several Kam-Sui languages of southern China have nine tones, including contour tones, assuming that checked syllables are not counted as having additional tones, as they traditionally are in China. Preliminary work on the Wobe language of Liberia and Ivory Coast and the Chatino languages of southern Mexico suggests that some dialects may distinguish as many as fourteen tones, but many linguists have expressed doubts, believing that many of these will turn out to be sequences of tones or prosodic effects.
Tone is carried by the word or syllable, so syllabic consonants such as nasals and trills may bear tone. This is especially common with syllabic nasals, for example in many Bantu and Kru languages, but also occurs in Serbo-Croatian.
|Sound change and alternation|
André-Georges Haudricourt established that Vietnamese tone originated in earlier consonantal contrasts, and suggested similar mechanisms for Chinese. It is by now well-established that Old Chinese did not have phonemically contrastive tone. The historical origin of tone is called tonogenesis, a term coined by James Matisoff. Tone is frequently an areal rather than a genealogical feature: That is, a language may acquire tones through bilingualism if influential neighboring languages are tonal, or if speakers of a tonal language shift to the language in question, and bring their tones with them. In other cases, tone may arise spontaneously, and surprisingly quickly: The dialect of Cherokee in Oklahoma has tone, but the dialect in North Carolina does not, although they were only separated in 1838.
Very often, tone arises as an effect of the loss or merger of consonants. (Such trace effects of disappeared tones or other sounds have been nicknamed Cheshirisation, after the lingering smile of the disappearing Cheshire cat in Alice in Wonderland.) In a non-tonal language, voiced consonants commonly cause following vowels to be pronounced at a lower pitch than other consonants do. This is usually a minor phonetic detail of voicing. However, if consonant voicing is subsequently lost, that incidental pitch difference may be left over to carry the distinction that the voicing had carried, and thus becomes meaningful (phonemic). We can see this historically in Panjabi: the Panjabi murmured (voiced aspirate) consonants have disappeared, and left tone in their wake. If the murmured consonant was at the beginning of a word, it left behind a low tone; if at the end, a high tone. If there was no such consonant, the pitch was unaffected; however, the unaffected words are limited in pitch so as not to interfere with the low and high tones, and so has become a tone of its own: mid tone. The historical connection is so regular that Panjabi is still written as if it had murmured consonants, and tone is not marked: The written consonants tell the reader which tone to use.
Similarly, final fricatives or other consonants may phonetically affect the pitch of preceding vowels, and if they then weaken to /h/ and finally disappear completely, the difference in pitch, now a true difference in tone, carries on in their stead. This was the case with the Chinese languages: Two of the three tones of Middle Chinese, the "rising" and "leaving" tones, arose as the Old Chinese final consonants /ʔ/ and /s/ → /h/ disappeared, while syllables that ended with neither of these consonants were interpreted as carrying the third tone, "even". Most dialects descending from Middle Chinese were further affected by a tone split, where each tone split in two depending on whether the initial consonant was voiced: Vowels following an unvoiced consonant acquired a higher tone while those following a voiced consonant acquired a lower tone as the voiced consonants lost their distinctiveness.
The same changes affected many other languages in the same area, and at around the same time (AD 1000–1500). The tone split, for example, also occurred in Thai, Vietnamese, and the Lhasa dialect of Tibetan.
In general, voiced initial consonants lead to low tones, while vowels after aspirated consonants acquire a high tone. When final consonants are lost, a glottal stop tends to leave a preceding vowel with a high or rising tone (although glottalized vowels tend to be low tone, so if the glottal stop causes vowel glottalization, that will tend to leave behind a low vowel), whereas a final fricative tends to leave a preceding vowel with a low or falling tone. Vowel phonation also frequently develops into tone, as can be seen in the case of Burmese.
Tone arose in the Athabascan languages at least twice, in a patchwork of two systems. In some languages, such as Navajo, syllables with glottalized consonants (including glottal stops) in the syllable coda developed low tones, whereas in others, such as Slavey, they developed high tones, so that the two tonal systems are almost mirror images of each other. Syllables without glottalized codas developed the opposite tone—for example, high tone in Navajo and low tone in Slavey, due to contrast with the tone triggered by the glottalization. Other Athabascan languages, namely those in western Alaska (such as Koyukon) and the Pacific coast (such as Hupa), did not develop tone. Thus, the Proto-Athabascan word for "water" *tuː is toneless toː in Hupa, high-tone tó in Navajo, and low-tone tù in Slavey; while Proto-Athabascan *-ɢʊtʼ "knee" is toneless -ɢotʼ in Hupa, low-tone -ɡòd in Navajo, and high-tone -ɡóʔ in Slavey. Kingston (2005) provides a phonetic explanation for the opposite development of tone based on the two different ways of producing glottalized consonants with either (a) tense voice on the preceding vowel, which tends to produce a high F0, or (b) creaky voice, which tends to produce a low F0. Languages with "stiff" glottalized consonants and tense voice developed high tone on the preceding vowel and those with "slack" glottalized consonants with creaky voice developed low tone.
The Bantu languages also have "mirror" tone systems, where the languages in the northwest corner of the Bantu area have the opposite tones of other Bantu languages.
Three Algonquian languages developed tone independently of each other and of neighboring languages: Cheyenne, Arapaho, and Kickapoo. In Cheyenne, tone arose via vowel contraction; the long vowels of Proto-Algonquian contracted into high-pitched vowels in Cheyenne, while the short vowels became low-pitched. In Kickapoo, a vowel with a following [h] acquired a low tone, and this tone later extended to all vowels followed by a fricative.