Tone sandhi

Tone sandhi is a phonological change that occurs in tonal languages. It involves changes to the tones assigned to individual words or morphemes, based on the pronunciation of adjacent words or morphemes. This change typically simplifies a bidirectional tone into a one-directional tone. Tone sandhi is a type of sandhi, which refers to fusional changes, and is derived from the Sanskrit word for "joining."

Languages with tone sandhi

Tone sandhi occurs to some extent in nearly all tonal languages, manifesting itself in different ways. Tonal languages, characterized by their use of pitch to affect meaning, appear all over the world, especially in the Niger-Congo language family of Africa and the Sino-Tibetan language family of East Asia, as well as other East Asian languages such as Kra-Dai, and Papuan languages. East and Southeast Asian languages tend to have larger tonal inventories compared to African languages. However, African languages frequently exhibit downdrift and mobility, forms of tone interaction. Tonality is also found in many Oto-Manguean and other languages of Central America, and Europe. However, in East and Southeast Asia, "paradigmatic replacement" is a more common form of tone sandhi, as one tone changes to another in a certain environment, whether or not the new tone is already present in the surrounding words or morphemes.. All the other syllables of the word must take their sandhi form. Mandarin Tone 3 Sandhi and Taiwanese Hokkien tone sandhi are both right-dominant.

In a left-dominant system, the leftmost tone tends to spread rightward.

Shanghainese is an example of a left-dominant system.

Hmong

The seven or eight tones of Hmong demonstrate several instances of tone sandhi. In fact the contested distinction between the seventh and eighth tones surrounds the very issue of tone sandhi (between glottal stop (-m) and low rising (-d) tones). High and high-falling tones (marked by -b and -j in the RPA orthography, respectively) trigger sandhi in subsequent words bearing particular tones. A frequent example can be found in the combination for numbering objects (ordinal number + classifier + noun): ib (one) + tus (classifier) + dev (dog) > ib tug dev (note tone change on the classifier from -s to -g).

Tone sandhi versus morphological tone change

Tone sandhi is compulsory as long as the environmental conditions that trigger it are met. It is not to be confused with tone changes that are due to derivational or inflectional morphology. For example, Cantonese has a derivational process known as changed tone, which only applies in certain semantic domains. The word (; ) means "sugar", whereas the derived word (; also written ) means "candy". Such a change is not triggered by the phonological environment of the tone, and therefore is not an example of sandhi.

Examples

Mandarin Chinese

Standard Chinese (Standard Mandarin) features several tone sandhi rules:

When there are two 3rd tones in a row, the first one becomes 2nd tone. E.g. 你好 (nǐ + hǎo > ní hǎo)

Molinos Mixtec

Molinos Mixtec, another Oto-Manguean language, has a much more complicated system of tone sandhi. The language has three tones (high, mid, or low, or 1, 2, or 3, respectively), and all roots are disyllabic, meaning that there are nine possible combinations of tones for a root or "couplet". The tone combinations are expressed here as a two digit number (high-low is represented as 13). Couplets are also classified into either class A or B, as well as verb or non-verb. A number of specific rules depending on these three factors determine tone change. One example of a rule follows:

"Basic 31 becomes 11 when following any couplet of Class B but does not change after Class A (except that after 32(B') it optionally remains 31"

ža²ʔa² (class B) "chiles" + ži³či¹ (class A) "dry" > ža²ʔa²ži¹či¹ "dry chiles" In Akan, tones at morpheme boundaries assimilate to each other through tone sandhi, the first tone of the second morpheme changing to match the final tone of the first morpheme.

For example:

:àkókɔ́ + òníní > àkókɔ́óníní "cockerel"

:ǹsóró + m̀má > ǹsóróḿmá "star(s)"

Motivations

Tone sandhi, especially the case of the Taiwanese Hokkien tone circle, often lacks intuitive phonetic explanations. Specifically, sandhi rules may target classes of phones not previously identified as natural, the conditioning environments may be disjoint, or the tone substitutions may occur without any reason.

This is because waves of sound change have hidden the original phonetic motivation of the sandhi rule. In the case of Chinese varieties, though, Middle Chinese tones can be used as natural classes for tone sandhi rules in modern varieties, showing that diachronic information needs to be considered to understand tone sandhi.

The phonetic unnaturalness of many tone sandhi processes have made it difficult for phonologists to express such processes with rules or constraints.

Phonologically, tone sandhi is often an assimilatory or dissimilatory process.

Mandarin Tone 3 sandhi, explained above, is an example of an Obligatory Contour Principle effect because it involves two tone 3 syllables next to each other. The first of the two tone 3's becomes a tone 2 to dissimilate from the other syllable.

Transcription

Sinologists sometimes use reversed Chao tone letters to indicate sandhi, with the left-facing letters of the IPA on the left for the underlying tone, and reversed right-facing letters on the right for the realized tone. For example, the Mandarin example of nǐ + hǎo > ní hǎo above would be transcribed:

The individual Unicode components of the reversed tone letters are .