Back vowels are vowels that are pronounced using the back of the tongue.

A coronal is a sound that is pronounced using the tip or the upper part of the tongue.

Retroflex sounds are difficult to pronounce.

Retroflex is a phonetic feature that does not exist in Japanese.

A dorsal sound is a sound that is pronounced by the back of the tongue approaching or touching the palate or pharynx.

A central vowel is a vowel that is pronounced in the central part of the tongue.

The central vowels in Japanese are 'a', 'e', 'o'.

Front vowels are pronounced using the front part of the tongue.

A front vowel is a vowel that is articulated with the front part of the tongue.

He pulled the door and entered the room.