How to distinguish loose vowels from tight vowels in phonetics?

Loose vowels, phonetic terms. Also known as "wide vowel". When the "tight vowel" is pronounced symmetrically, the muscles of the vocal organs such as lips, tongue and soft palate are relatively relaxed, and the timbre of * * * is not bright.

Loose vowels are more common in unstressed syllables. For example, the second word "brother" in Mandarin is lightly pronounced, and the vowel [? ] is vague and a loose vowel.

Phonology is a branch of linguistics. The study of human speech. This paper mainly studies the pronunciation mechanism, phonetic characteristics and changing rules of language in speech. Because its research content is related to pronunciation action (physiological phenomenon), sound characteristics (physical phenomenon) and listening feeling (psychological effect).

Different language families of human beings have their own phonetic features, so the study of modern phonetics needs to be based on the knowledge of natural science and social science. In the west, the word phonetics comes from the Greek word φ ω ν ε ι ο? , meaning sound.

The early research covers a wide range, including not only the study of phonetic features, but also the pronunciation or pinyin of language, phonology and so on. In the study of traditional phonology in China, the description and classification of phonetics also belong to the category of phonetics. However, with the development of modern scientific phonetics, the classification is more and more detailed and the definition is more and more strict. Phonetics refers to the study of the characteristics of pronunciation itself.