Tone (linguistics)

Tone is the use of pitch in language to distinguish words. All languages use intonation to express emphasis, contrast, emotion, or other such elements, but not every language uses tone to distinguish lexical meaning. When this occurs, tones are phonemes (discrete speech sounds), just like consonants and vowels, and they are occasionally referred to as tonemes.

A slight majority of the languages in the world are tonal. However, most Indo-European languages, which include the majority of the most widely-spoken languages in the world today, are not tonal, with the exception of the Indo-Aryan language Punjabi.

The way in which tone is used in a particular language leads to the language being classified either as a tonal language or a pitch accent language. In a prototypical tonal language such as Chinese, the tone of each syllable can be independent of the other syllables in the word, and many words are differentiated only by the tones associated with them. In many African tone languages, since words are longer, there are fewer minimal pairs for tone, and tone may not be assigned to every syllable of a word. In a pitch accent language, there is typically only one tone-accented syllable or mora per word. For example Somali has one high tone per word. In Japanese, pitch accent refers to a drop in pitch; words contrast depending on which syllable this drop follows. Some words in Japanese contain no pitch accent at all. While many linguists maintain a difference between tone languages and pitch accent languages, the linguist Larry Hyman has argued that there is no prototypical pitch accent language and that all languages that use tone phonemically should be classified as tone languages.

Tonal languages
Languages that are tonal include:
 * Some of the Sino-Tibetan languages, including the numerically most important ones. Most forms of Chinese are strongly tonal (an exception is Shanghainese, where the system has collapsed to one of pitch accent); while some of the Tibetan languages, including the standard languages of Lhasa and Bhutan and Burmese are more marginally tonal. However, Nepal Bhasa, the original language of Kathmandu, is non-tonal, as are several Tibetan dialects and many or most of the other Tibeto-Burman languages.
 * In the Austro-Asiatic family, Vietnamese and its closest relatives are strongly tonal. Other languages of this family, such as Mon, Khmer and the Munda languages, are non-tonal.
 * The entire Tai-Kadai family, spoken mainly in China, Vietnam, Thailand, and Laos, is strongly tonal.
 * The entire Hmong-Mien languages family is strongly tonal.
 * Many Afro-Asiatic languages in the Chadic, Cushitic and Omotic families have register-tone systems, such as Chadic Hausa. Many of the Omotic tone systems are quite complex. However, many other languages, such as Cushitic Somali, have pitch-accent systems rather than tone.
 * The vast majority of Niger-Congo languages, such as Ewe, Maninka, Yoruba, Lingala and the Nguni languages, have register-tone systems. The Bantu languages fall under this group. Many of the Kru systems are quite complex. Notable non-tonal languages are Swahili and Wolof.
 * Possibly all Nilo-Saharan languages have register-tone systems.
 * All Khoisan languages in southern Africa have contour-tone systems.
 * Slightly more than half of the Athabaskan languages, such as Navajo, have simple register-tone systems (languages in California, Oregon and a few in Alaska are excluded), but the languages that have tone fall into two groups that are mirror images of each other.
 * All Oto-Manguean languages are tonal. Most have register-tone systems, others contour systems and many have combined systems.
 * The Kiowa-Tanoan languages.
 * Scattered languages of the Amazon basin, usually with rather simple register-tone systems.
 * Scattered languages of New Guinea, usually with rather simple register-tone systems.
 * Some European-based creole languages, such as Saramaccan and Papiamentu, have tone from their African substratum languages.
 * In Yeniseian languages, tone is comcomitant with other features and it depends on the interpretation whether these languages are considered tonal or not.

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.

Some Indo-European languages are usually characterised as tonal, such as Lithuanian, Slovenian, Serbo-Croatian, Limburgish, Swedish and Norwegian; more correctly, however, they are pitch accent languages, as only the tone on the stressed syllable can have any effect on the meaning. Ancient Greek and Vedic Sanskrit were also pitch-accent languages. (In practice, the pitch alone only rarely distinguished the meaning in these two languages. A famous example of such a case is from Aristophanes' Frogs (l. 304), where Aristophanes refers to an actual occurrence at the performance of Euripides' Orestes where an actor had pronounced galn' horō "I see calm waters" with so much empathy that it came out galên horō "I see a weasel".)

However, the Indo-European language Punjabi is clearly a tonal language, where the tones arose as a reinterpretation of different consonant series in terms of pitch, as happened in most of the Chinese languages.

Origin of tone
Tone is frequently an areal rather than a genetic feature: that is, a language may acquire tones through bilingualism if influential neighboring languages are tonal, or if speakers of a tonal language switch to the language in question. 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.

An interesting question is how tones arise in a language, i.e. tonogenesis. In the Chinese languages they arose as a reinterpretation of initial and final consonants. Middle Chinese, for example, had three tones (rising, "departing", and level), which are said to have arisen from Old Chinese final consonants (, /s/, or neither of these). Most later dialects were affected by a tonal split, where each tone split into two depending on whether the initial consonant was voiced or unvoiced; vowels following an unvoiced consonant acquired a high tone while those following a voiced consonant acquired a low tone, and this distinction became phonemic when voiced consonants lost their voicing. This is an example of Cheshirisation.

These same changes affected many other languages in the same area, around the same time (AD 1000 - 1500). The tone split, for example, also occurred in Thai, Vietnamese, and Lhasa 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), whereas a final fricative tends to leave a preceding vowel with a low or falling tone. Vowel phonation also frequently develops into tone, as in the case of Burmese.

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] became low tone, and this tone later extended to all vowels followed by a fricative.

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. 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" *tu· is toneless to· in Hupa, high-toned tó in Navajo, and low-toned tù in Slavey, while Proto-Athabascan * "knee" is toneless ' in Hupa, low-toned -gòd in Navajo, and high-toned ' 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) accompaning tense voice (with high F0) or (b) creaky voice (with low F0) on the preceding vowel. 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.

Tone as a distinguishing feature
Most languages use intonation (that is, pitch) to convey grammatical structure or emphasis (see phonology), but this does not make them tonal languages in this sense. In these cases, tones can change how the audience is intended to interpret a word (e.g. sarcastically), but in tonal languages, the tone is an integral part of a word itself. Thus minimal pairs can exist in such a language, distinguished only by a change of tone.

To illustrate how tone can affect meaning, let us look at the following example from Mandarin, which has five tones, which can be indicated by diacritics over vowels:


 * 1) A long, high level tone: ā
 * 2) Starts at normal pitch and rises to the pitch of tone 1: á
 * 3) A low tone, dipping down briefly before slowly rising to the starting level of tone 2: ǎ
 * 4) A sharply falling tone, starting at the height of tone 1 and falling to somewhere below tone 2's onset: à
 * 5) A neutral tone, sometimes indicated by a zero or a dot (·), which has no specific contour; the actual pitch expressed is directly influenced by the tones of the preceding and following syllables. Mandarin speakers refer to this tone as the "light tone" (輕聲).

These tones can lead to one syllable, e.g. "ma", having numerous meanings, of which five are exemplified below, depending on the tone associated with it, so that "mā" glosses as "mother", "má" as "hemp", "mǎ" as "horse", "mà" as "scold", and toneless "ma" at the end of a sentence acts as an interrogative particle. This differentiation in tone allows a speaker to create the (not entirely grammatical) sentence:


 * 妈妈骂马的麻吗? (in traditional characters 媽媽罵馬的麻嗎?)
 * māma mà mǎ de má ma?
 * "Is Mother scolding the horse's hemp?"

A well-known tongue-twister in the Thai language is:


 * ไหมใหม่ไหม้ไหม
 * măi mài mâi măi
 * "Does new silk burn?"

(Tones can change over time, while retaining their original spelling. The Thai spelling of the final word in the tongue-twister - ไหม - indicates a rising tone, but is now commonly pronounced with a high tone - māi. A newer spelling - มั้ย - occasionally appears.)

Tones can interact in complex ways through a process known as tone sandhi.

Register and contour tones
Tonal languages fall into two broad categories: Register tone systems and contour tone systems. Mandarin has a contour tone system, where the distinguishing feature of the tones are their shifts in pitch (their pitch shapes or contours, such as rising, falling, dipping, or peaking) rather than simply their pitch relative to each other as in a register tone system. Register tone systems are found in Bantu languages and throughout Africa. In some 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 the Kru languages, though in such cases the register tones may be analysed as being 'level' (unvarying pitch) contour tones.

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 clause may be lower than that of a low tone at the beginning, because average pitch tends to decrease with time in a process called downdrift.

The term 'register', when not in the phrase 'register tone', is used to indicate vowel phonation combined with tone in a single phonological system. Burmese and Khmer, for example, are register languages. Burmese is usually considered a tonal language and Khmer a vowel-phonation language, but in both cases differences in relative pitch or pitch contours are correlated with vowel phonation, so that neither exists independently.

Notational systems
Due to the fact that tonal languages are found all over the world, several systems to mark tone have developed independently. In Asian and Meso-American contexts, numerical systems are most common, whereas accent marks are used mainly in African contexts.

Africa
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. Contour tones are then indicated 14, 21, etc.

Asia
In the Chinese tradition, numerals are assigned to various tones. For instance, Standard Mandarin has five tones, and the numerals 1, 2, 3, and 4 are assigned to four tones, and the neutral tone is left numberless. Chinese dialects are traditionally described in terms of eight tones (six tones, from the perspective of modern linguistics), though many dialects do not have all of them. Outside standard Mandarin, the numerals 1 to 8 are assigned to these tones based on their historical origin. In neither of these systems does the numeral have anything to do with the pitch values of the tones. Tone 5, for example, has drastically different realizations in different dialects.

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):

A mid-level tone would be indicated by /33/, a low level tone /11/, etc.

The Thai language has five tones: high, mid, low, rising and falling. It uses an alphabetic writing system 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:

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.

The Japanese language does not have tone, but does have pitch accent, so that 雨 áme (rain), with a drop in pitch (a downstep) after the first syllable, is distinguished from あめ ame (candy), which has no downstep.

The Americas
Several North American languages have tone, one of which is 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. 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, Chinantec, and Otomí, some of which have as many as 12 different tones (Zoogocho Zapotec) 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).

Europe
Both Swedish and Norwegian have a phenomenon that is often called "tone", but it is better understood as a pitch accent, as it appears only in words of two or more syllables. (Tones, according to the linguistic definition, are found on every syllable in tone languages.) This pitch accent is mostly used prosodically, but also to differentiate two-syllable words depending on their morphological structure. These accents are usually referred to as accent 1 and accent 2 (or acute accent and grave accent), respectively. For further explanation and examples, see the Swedish and Norwegian language articles.

Number of tones
In theory, there can be endless kinds of tonal variations. Although classified here according to their pitch values from 1 to 5, tones can actually change in pitch. Some tones change twice within a syllable. Therefore, theoretically, there can be a variation of 5*5*5 = 125 different tones. However, if tones are not distinguishable, they are obsolete. Practically, the tones will shift until they can be distinguished.

The living language that has the most tones currently is Ai-Cham (錦話), a member of Kam-Sui languages in the Tai-Kadai language family. It has a total number of 11 tones; Pinghua has 10 tones.