A'ou (阿欧方言) or Red Gelao (红仡佬语) is an endangered Gelao language spoken by fewer than 100 people in Guizhou, China.^[2] Only the Hongfeng (红丰) and Bigong (比贡) dialects are still spoken, each with only a few dozen speakers.

The main dialects of A'ou, which all have limited mutual intelligibility, are:

• Hongfeng (红丰)^[3]
• Bigong (比贡)^[4]
• Qiaoshang (桥上)^[5] (extinct)

Only one elderly speaker of the Houzitian (猴子田) dialect was found in 2013, and it is likely now extinct.^[6]

Mulao (木佬) is sometimes also included, in addition to Yi (羿), an extinct A'ou variety of Sichuan.^[7]