A with diaeresis (Ӓ ӓ; italics: Ӓ ӓ) is a letter of the Cyrillic script used in the Khanty, Kildin Sami, and Mari languages. Also, this letter was once used in the Gagauz language (surrogate's АЬ).
A with diaeresis (Cyrillic) Wikipedia
In Mari, and Gagauz language this letter represents the near-open front unrounded vowel, /æ/.
In Kildin Sami this letter represents the open back unrounded vowel /a/ following a palatalized (sometimes also called "half-palatalized") velar nasal /nʲ/ or one of the alveolar stops /tʲ/ or /dʲ/.
In Khanty language this letter represents the near-open central vowel /ɐ/.
Some languages represent as /ja/, like in letter "Я".