1, in: I was given first, then the tip of the tongue pressed against the upper gum, and the soft palate drooped, allowing air to flow out of the nasal cavity.

2, ing: I first, then my tongue shrinks backwards, the base of my tongue is against the soft palate, and the airflow comes out of the nasal cavity.

3. According to the textbook, one is the front nasal rhyme and the other is the back nasal rhyme. In is pronounced with the mouth, and ing is pronounced with the nasal cavity. The tongue is basically flat when pronounced in. When doing ing, the tongue moves backwards, and the root of the tongue will block the passage between the nose and mouth, so that the airflow can only come out of the nasal cavity.

4. Anterior nasal sound, ING- posterior nasal sound In- sound is in front, ING- sound is at the root of the tongue, and behind.

There are sixteen nasal vowels in Mandarin * * * which are: an ian uan ü an en in uen ü n ang ng ng eng ong. Putonghua clearly distinguishes two groups of vowels ending in -n and -ng. Vowels ending in -n are called anterior nasal vowels, and vowels ending in -ng are called posterior nasal vowels.

Front nasal rhyme? The pronunciation skill of -n is that at the end of pronunciation, the tongue is close to the gum, and the tongue and gum in the mouth form obstacles and are completely blocked, and the soft palate droops to ventilate the nasal cavity.

A vowel followed by a nasal consonant.

There are sixteen nasal vowels in Putonghua * * * which is an ian uan ü an en in uenün ang ang ang ng ONG yung yung.

Mandarin is clearly divided into two groups of vowels ending in -n and -ng. Vowels ending in -n are called anterior nasal vowels, and vowels ending in -ng are called posterior nasal vowels.

References:

Baidu encyclopedia-front nasal sound

References:

Baidu encyclopedia-post-nasal sound