Yangon Tribe

In general, it is unfair to say that Unggoy are not nearly as intelligent as other species. Their minds simply work in different ways. As a species, Unggoy can be courageous, cowardly, intelligent, stupid - but they tend toward the extremes. Many tribes seem to be genetically inclined towards lower intelligence - while others are exactly the opposite.
The Yangon Tribe hails from the far north of Balaho, where the geothermal vents are fewer in number, making the environment less durable and more harsh. As a result, its inhabitants have been forced to adapt to this lifestyle with their wits, unable to rely solely on numbers as their southern brethren are. Yangon Unggoy are isolated from the rest of the planet by seasonal storms, closing off their settlements to travel. The window of opportunity to leave or enter is short, only a few weeks, and for the rest of the year the only way is to travel via Phantom or Spirit dropship, a scarce commodity on Balaho.
The isolation of the Yangon has produced a radically different breed of Unggoy. While not as physically hardy as others, they have a higher average intellect, and are able to pick up skills far quicker. This makes them good candidates for technicians and communications crew, filling posts too difficult for regular Unggoy, but too menial for Sangheili or Jiralhanae. At least one Lance was aboard the Bringer of Holy Light, a Covenant Assault Carrier, serving as technicians and maintenance support crew when it disappeared. Others are employed as Fleet Traffic Control officers in colonies with heavy amounts of shipping traffic.