International phonetic symbols are distinguished from ordinary letters by brackets []. In addition, for the convenience of recording, the International Phonetic Society has also stipulated a set of "descriptive symbols" for some important phonetic accompaniment phenomena.
"Contemporary symbols" and "special symbols". For example, the symbol "* *" is nasalized, "ph" is strongly aspirated, "P" is weakly aspirated, "A:" is full length A, "A." is half length A, "* *" is light tone (* *) and so on. General symbols and special symbols are not illustrated.
Symbol:
The International Phonetic Alphabet was created by British and French scholars, which is mainly applicable to the annotation of Indo-European languages, African languages and some minority languages. After its publication, it became popular in European linguistics. Most Americans still use their own spelling and American Indian symbols.
There are only eight tone symbols in the international phonetic alphabet, which is not enough to study and describe tonal languages. Zhao Yuanren put forward the Latin alphabet of tones, which was published in Phonetics Teacher 1930. It is applicable to all tonal language and has been adopted by most international scholars. The four tones of Putonghua are ā, á, m 4 and à, which become common sense.