Sandhi

Sandhi can be either

• internal, at morpheme boundaries within words, such as syn- + pathy: sympathy, or
• external, at word boundaries, such as the pronunciation "tem books" for ten books in some dialects of English. The linking /r/ process of some dialects of English ("I saw-r-a film" in British English) is a kind of external sandhi, as are French liaison (pronunciation of usually silent final consonants of words before words beginning with vowels) and Italian raddoppiamento fonosintattico (lengthening of initial consonants of words after certain words ending in vowels).

It may be extremely common in speech, but sandhi (especially external) is typically ignored in spelling, as is the case in English (exceptions:the distinction between a and an; the prefixes syn-, in-, en-, and con-). Sandhi is, however, reflected in the orthography of Sanskrit, Sinhala, Telugu, Marathi, Pali and some other Indian languages, as with Italian in the case of compound words with lexicalised syntactic gemination.

External sandhi effects can sometimes become morphologised (apply only in certain morphological and syntactic environments) as in Tamil[1][2] and, over time, turn into consonant mutations.

Most tonal languages have tone sandhi in which the tones of words alter according to certain rules. An example is the behavior of Mandarin Chinese. When in isolation, tone 3 is often pronounced as a falling-rising tone. When a tone 3 occurs before another tone 3, however, it changes into tone 2 (a rising tone), and when it occurs before any of the other tones, it is pronounced as a low falling tone, with no rise at the end. A simple example occurs in the common greeting 你好 nǐ hǎo (with two words containing underlying tone 3), normally pronounced ní hǎo.

In Japanese phonology, sandhi is primarily exhibited in rendaku (consonant mutation from unvoiced to voiced when not word-initial, in some contexts) and conversion of つ or く (tsu, ku) to a geminate consonant (orthographically, the sokuon っ), both of which are reflected in spelling – indeed, the っ symbol for gemination is morphosyntactically derived from つ, and voicing is indicated by adding two dots as in か／が ka, ga, making the relation clear. It also occurs much less often in renjō (連声), where, most commonly, a terminal /n/ on one morpheme results in an /n/ (or /m/) being added to the start of the next morpheme, as in 天皇: てん ＋ おう → てんのう (ten + ō = tennō); that is also shown in the spelling (the kanji do not change, but the kana, which specify pronunciation, change).