Advanced and retracted tongue root

Advanced tongue root (ATR)
◌̘
IPA number	417

Retracted tongue root (RTR)
◌̙
IPA number	418

In phonetics, advanced tongue root and retracted tongue root, abbreviated ATR or RTR, are contrasting states of the root of the tongue during the pronunciation of vowels in some languages, especially in West and East Africa but also in Kazakh and Mongolian. It used to be suggested that it was the basis for the distinction between tense and lax vowels in European languages such as German, but this no longer seems tenable.

Advanced tongue root, abbreviated ATR or +ATR, also called expanded, involves the expansion of the pharyngeal cavity by moving the base of the tongue forward and often lowering the larynx during the pronunciation of a vowel. The lowering of the larynx sometimes adds a breathy quality to the vowel.

Voiced stops such as [b], [d], [g] can often involve non-contrastive tongue root advancement whose results can be seen occasionally in sound changes relating stop voicing and vowel frontness such as voicing stop consonants before front vowels in the Oghuz Turkic languages or in Adjarian's law: the fronting of vowels after voiced stops in certain dialects of Armenian.

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