Kakais is the name given by many in Iraq to members of the Ahl-i Haqq religion. They are just one of several heterodox communities in Iraqi Kurdistan. Although some see their origin in pre-Islamic times, they apparently emerged against the backdrop of the earlier Mongol invasion in the 13th century and the Ottoman-Safavid rivalries in the 16th century. Some claim that they were founded in Hawraman by a Sayyid Ishaq, subsequently called Sultan Sohak in the 14th century. They live scattered over Iraqi Kurdistan and especially in the Guran district and Azerbaijan province of Iran, where they are usually referred to as Yaresan.
The Kakais are usually rather secretive about their religious beliefs and when queried employ taqiya or dissimulation. Linguistically, the Kakais are also rather diverse and even have their own language, Macho, which is a branch of the Kurdish language or dialect Gurani. However, most Kakais also use whatever happens to be the main language of their surroundings, including Sorani Kurdish, Turkoman, or Arabic.
Historical Dictionary of the Kurds. Michael M. Gunter.