a: When pronouncing, the lips should be naturally widened, the tongue should be flat, the middle of the tongue should be slightly raised, and the vocal cords should tremble.

o: When pronouncing, the lips should be rounded and slightly raised, the tongue should be retracted, the back of the tongue should be raised, the tongue should be centered, and the vocal cords should vibrate.

e: When pronouncing, the mouth should be half-open, the tongue should be positioned back, the corners of the mouth should be flattened to both sides, and the vocal cords should vibrate.

i: When pronouncing, the mouth should be slightly open and flat, the tip of the tongue should be against the lower gums, the surface of the tongue should be raised, close to the upper hard palate, and the vocal cords should vibrate.

u: When pronouncing, the lips should be rounded and protruded into small holes, the back of the tongue should be raised, and the vocal cords should vibrate.

ü: When pronouncing, the lips should be rounded and nearly closed, the tip of the tongue should be against the lower gums, the front of the tongue should be raised, and the vocal cords should vibrate.

b: When pronouncing, the lips should be tightly closed to block the airflow, and then the lips should be suddenly released to allow the airflow to rush out, and the pronunciation should be light and short.

p: When pronouncing, the lips should be tightly closed to block the airflow, and then the lips should be suddenly released to allow the airflow to burst into sounds.

m: When pronouncing, the lips should be tightly closed, the tongue should be retracted, the airflow should come out of the nasal cavity, and the mouth should be opened to vibrate the vocal cords.

f: When pronouncing, the upper teeth should touch the lower lip to form a narrow gap, so that the air can be squeezed out of the gap and the friction will make a sound.

d: When pronouncing, the tip of the tongue should be pressed against the upper gums. After holding in the airflow, it should be suddenly released. The airflow should burst out of the mouth and burst into sounds.

t: When pronouncing, the tip of the tongue should be pressed against the upper gums. After holding the breath, it should suddenly leave, and the air should burst out of the mouth.

n: When pronouncing, the tip of the tongue should be against the upper gums, the airflow should pass through the nasal cavity, and at the same time, the obstruction of the tongue tip should be overcome, and the vocal cords should vibrate.

l: When pronouncing, the lips should be slightly open, the tip of the tongue should be pressed against the upper gums, so that the vocal cords vibrate, and the airflow should flow out from both sides of the tongue tip.

g: When pronouncing, the front of the tongue base should be against the soft palate to block the airflow, and the airflow should be allowed to break through the obstruction of the tongue base to burst into sounds.

k: When pronouncing, the front of the tongue base should be against the upper soft palate to obstruct the airflow. The airflow should be allowed to break through the obstruction of the tongue base to make the sound burst out.

h: When pronouncing, the base of the tongue should be raised and close to the soft palate to form a narrow slit, so that the airflow can be squeezed out of the slit and rubbed to form a sound.

j: When pronouncing, the tip of the tongue should be against the lower incisors, and the front of the tongue should be close to the hard palate, so that the airflow rushes out from the narrow gap and rubs into the sound.

q: When pronouncing, the front of the tongue should be against the hard palate, so that the airflow breaks through the obstruction of the base of the tongue and the friction becomes a sound.

x: When pronouncing, the tip of the tongue should be against the lower incisors, and the front of the tongue should be raised close to the hard palate to form a narrow slit, so that the airflow can be squeezed out of the slit and rubbed to form a sound.

zh: When pronouncing, the tip of the tongue should be upturned and pressed against the front of the hard palate. There should be weak airflow to break away from the obstruction of the tongue tip, squeeze out from the gap, and rub into the sound.

ch: When pronouncing, the tip of the tongue should be upturned and pressed against the front of the hard palate. There should be strong airflow to break away from the obstruction of the tongue tip, squeeze out from the gap, and rub into the sound.

sh: When pronouncing, the tip of the tongue should be upturned and close to the front of the hard palate, leaving a narrow gap so that the airflow can be squeezed out of the narrow gap and rubbed to form a sound.

r: When pronouncing, the tip of the tongue should be upturned, close to the front of the hard palate, leaving a narrow gap, and the throat should be pronounced hard so that the airflow is squeezed out of the narrow gap, friction becomes a sound, and the vocal cords vibrate. .

z: When pronouncing, the tip of the tongue should be pressed against the back of the upper incisors to obstruct the airflow. The weaker airflow should be allowed to break through the obstruction of the tongue tip and squeeze out from the narrow gap to produce a fricative sound.

c: When pronouncing, the tip of the tongue should be against the back of the upper incisors to block the airflow. The strong airflow should be squeezed out from the gap and rubbed to form a sound.

s: When pronouncing, the tip of the tongue should be close to the back of the upper incisor, leaving a narrow gap so that the airflow can be squeezed out from the narrow gap at the tip of the tongue and rubbed to form a sound.

y: When pronouncing, the mouth should be slightly open and flat, the tip of the tongue should be against the lower gums, the surface of the tongue should be raised, close to the upper hard palate, and the vocal cords should vibrate.

w: When pronouncing, the lips should be rounded and protruded into small holes, the back of the tongue should be raised, and the vocal cords should vibrate.

ai: When pronouncing, pronounce the a sound first, and then slide to i so that the airflow is not interrupted and the pronunciation is light and short.

ei: When pronouncing, pronounce the e sound first, then slide to i so that the airflow is not interrupted, and the corners of the mouth should be spread to both sides.

ui: When pronouncing, the pronunciation of u should be light and short, and then slide towards ei, and the shape of the mouth should change from round to flat.

ao: When pronouncing, pronounce the sound a first, then retract the tip of the tongue, lift the base of the tongue upward, make the mouth shape into a circle, and then gently slide towards o.

ou: When pronouncing, the o sound should be pronounced first, the lips should gradually close together, the base of the tongue should be raised, and the shape of the mouth should change from large round to small round.

iu: When pronouncing, pronounce i first, then slide toward ou, and the mouth shape should change from flat to round.

ie: When pronouncing, pronounce i first, then e, so that the airflow is not interrupted.

üe: When pronouncing, pronounce the sound ü first, then slide towards e, and the mouth shape should change from round to flat.

er: When pronouncing, the tongue should be centered to pronounce the e sound, and then the tip of the tongue should be curled toward the hard palate, and the two letters should be pronounced at the same time.

an: When pronouncing, the a sound should be pronounced first, and then the tip of the tongue should be gradually raised to press the upper gum to pronounce the n sound.

en: When pronouncing, the sound of e should be pronounced first, then the surface of the tongue should be raised, the tip of the tongue should be pressed against the upper gums, and the airflow should be released from the nasal cavity to pronounce the sound of n.

in: When pronouncing, the i sound should be pronounced first, then the tip of the tongue should be against the back of the lower incisor, the tongue surface should gradually reach the hard palate, and the airflow should be released from the nasal cavity, and the n sound should be pronounced.

un: When pronouncing, the u sound should be pronounced first, then the tip of the tongue should be pressed against the upper gums, and then the n sound should be pronounced, and the airflow should be released from the nasal cavity.

ün: When pronouncing, the sound of ü should be pronounced first, and then the tongue should be raised and pressed against the upper gums to allow the airflow to escape from the nasal cavity and the sound of n should be pronounced.

ang: When pronouncing, the sound of a should be pronounced first, then the base of the tongue should be pressed against the upper soft palate, the airflow should be released from the nasal cavity, and the sound of the back nasal ending ng should be pronounced.

eng: When pronouncing, the e sound should be pronounced first, then the tip of the tongue should be pressed against the lower gum, the base of the tongue should be retracted against the soft palate to produce the ng sound, and the airflow should be released from the nasal cavity.

ing: When pronouncing, the tip of the tongue should touch the lower gums, the surface of the tongue should rise to the hard palate, and the nasal cavity should make a sound.

ong: When pronouncing, the o sound should be pronounced first, then the base of the tongue should be retracted to press against the soft palate, the tongue surface should be raised, the lips should be rounded, and the nasal cavity should sound.

Extended information:

Hanyu Pinyin is the pinyin scheme for spelling the standard language of the Han nationality.

Hanyu Pinyin is based on the Beijing phonetic system as the phonetic standard. Beijing dialect is also a typical representative of the northern dialect with the largest territory and largest population in China.

The "Hanyu Pinyin Scheme", which explains the usage and standards of Chinese Pinyin, is the national standard for the Chinese Pinyin text scheme, and is also an international standard stipulated by the United Nations for spelling Chinese names, place names and special words. It is the pinyin scheme legally mandated by the People's Republic of China and the State, and is the international standard for spelling special nouns and words related to China in the world's documentation work.

On February 11, 1958, the Fifth Session of the First National People's Congress officially passed the "Chinese Pinyin Plan" and approved its promulgation and implementation.

The "Hanyu Pinyin Plan" is a plan that uses the internationally accepted Latin alphabet and a phonemic syllable structure to spell Mandarin with Beijing pronunciation as the standard pronunciation.

Reference materials:

Chinese Pinyin letters? Baidu Encyclopedia