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 is doing exercises to strengthen his genioglossus muscle.

The hyoid muscle is an important muscle that connects the larynx and the tongue.

He used to work as a low-ranking government official.

I feel ear pain because the stapedius is inflamed.