Ithorian (Earth-2356)

Ithorians, commonly referred to as hammerheads, are a sentient species from the planet Ithor, though they also have at least one settlement on Takobo, known as Hammertown. They have a unique set of twin mouths on opposite sides of their necks. They were called leathernecks as an insult by Imperial Stormtroopers. Their unique throat structure prevent them from speaking Galactic Basic, although they can understand it. There are a number of devices that allowe translation from Ithorese into Basic.

Source

 * https://starwars.fandom.com/wiki/Ithorian