He is an expert in osteology.

He underwent surgery on the depressor septi nasi.

In Sanskrit phonology, retroflex sounds play an important role.

A back vowel is a sound where the back of the tongue approaches the palate.

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.