Phonetic complement

A phonetic complement is a phonetic symbol used to disambiguate word characters (logograms) that have multiple readings, in mixed logographic-phonetic scripts such as Egyptian hieroglyphs, Akkadian cuneiform, Japanese, and Mayan.

Written English has few logograms, primarily numerals, and therefore few phonetic complements. An example is the "nd" of "2nd" 'second', which avoids ambiguity with 2 standing for the word 'two'. Hypothetically, if English had a more developed system of phonetic complements parallel with the scripts mentioned above, there might be a convention of writing "2ble" for 'double', "2ple" for 'couple', "2ary" for 'February' (the second month), "b2y" for 'binary', "2r" for 'pair', "o2r" for 'other' (which historically meant 'second'), "2in" for 'twin', "2ni" 'Gemini' ("the Twins"), etc.

In cuneiform

In Sumerian, the single word "kur" had two meanings: 'hill' and 'country'. Akkadian, however, had separate words for these two meanings: "šadú" 'hill' and "mātu" 'country'. When Sumerian cuneiform was adapted for writing Akkadian, this was ambiguous because both words were written with the same character (conventionally transcribed KUR, after its Sumerian pronunciation). To alert the reader as to which Akkadian word was intended, the phonetic complement "-ú" was written after KUR if hill was intended, so that the characters KUR-ú were pronounced "šadú," whereas KUR without a phonetic complement was understood to mean "mātu" 'country'.

Phonetic complements also indicated the Akkadian nominative and genitive cases.

Phonetic complements should not be confused with determinatives that indicated a category of the word it preceded or followed. For example, the sign DINGIR often precedes names of gods, as LUGAL does for kings. It is not believed that determinatives were pronounced.

In Japanese

As in Akkadian, Japanese borrowed a logographic script, Chinese, designed for a very different language. The Chinese phonetic components built into these "kanji" do not work when they are pronounced in Japanese, and there is not a one-to-one relationship between them and the Japanese words they represent.

For example, the kanji 生, pronounced "shō" or "sei" in borrowed Chinese vocabulary, stands for several native Japanese words as well. When these words have inflectional endings (verbs/adjectives and adverbs), the end of the stem is written phonetically:
*生 "nama" 'raw' or "ki" 'alive'
*生う [生u] "ou" 'expand'
*生きる [生kiru] "ikiru" 'live'
*生かす [生kasu] "ikasu" 'arrange'
*生ける [生keru] "ikeru" 'live'
*生む　 [生mu] "umu" 'produce'
*生まれる or 生れる [生mareru or 生reru] "umareru" 'be born'
*生える [生eru] "haeru" 'grow' (intransitive)
*生やす [生yasu] "hayasu" 'grow' (transitive)as well as the hybrid Chinese-Japanese word
*生じる [生jiru] "shōjiru" 'occur'

These phonetic characters are called "okurigana." They are used even when the inflection of the stem can be determined by a following inflectional suffix, so the primary function of "okurigana" for many kanji is that of a phonetic complement.

Generally it is the final syllable containing the inflectional ending is written phonetically. However, in adjectival verbs ending in "-shii," and in those verbs ending in "-ru" in which this syllable drops in derived nouns, the final two syllables are written phonetically. There are also irregularities. For example, the word "umareru" 'be born' is derived from "umu" 'to bear, to produce'. As such, it may be written 生まれる [生mareru] , reflecting its derivation, or 生れる [生reru] , as with other verbs ending in elidable "ru."

In Chinese

Chinese never developed a system of purely phonetic characters. Instead, about 90% of Chinese characters are compounds of a determinative (called a 'radical'), which may not exist independently, and a phonetic complement indicates the approximant pronunciation of the morpheme. However, the phonetic element is basic, and these might be better thought of as characters used for multiple near homonyms, the identity of which is constrained by the determiner. Due to sound changes over the last several millennia, the phonetic complements are not a reliable guide to pronunciation.

References

* [http://www.sron.nl/~jheise/akkadian/cuneiform.html#phoneticcompl Phonetic complement]