Only a few words of the Yeerk language are known, but all stated will be here.
- Andalite bandits - What the Yeerks call the Animorphs because they think they're Andalites who survived the battle in Earth's orbit.
- Beast Elfangor - The Yeerk name for Elfangor-Sirinial-Shamtul.
- Dapsen - A swear word of some kind.
- Filshig - Another swear word.
- Gashad - A warrant issued by the Council of Thirteen to kill a criminal on sight.
- Kandrona - The name of the Yeerk sun, and it's life-giving rays, as well as the device that generates the rays.
- Madra - A small, bright moon orbiting the Yeerk homeworld.
- Veleek - Pet. A creature the Yeerks found on Saturn and Visser Three named Veleek.