An auxiliary device charging case is used to facilitate translation features of a mobile computing device or auxiliary device. A first user, who may be a foreign language speaker, holds the charging case and speaks into the charging case. The charging case communicates the received speech to the mobile computing device, either directly or through the auxiliary device, which translates the received speech into a second language for a second user, who is the owner of the mobile computing device and auxiliary device. The second user may provide input in the second language, such as by speaking or typing into the auxiliary or mobile computing device. The mobile computing device may translate this second input to the first language, and transmit the translated input to the charging case either directly or through the auxiliary device. The charging case may output the translated second input to the first user, such as through a speaker or display screen.