Northern Luzon languages in the context of Cordillera Central (Luzon)

Iloco (also Ilóko, Ilúko, Ilocáno or Ilokáno; /iːloʊˈkɑːnoʊ/; Iloco: Pagsasaó nga Ilóko) is an Austronesian language primarily spoken in the Philippines by the Ilocano people. It is one of the eight major languages of the Philippines with about 11 million speakers and ranks as the third most widely spoken native language. Iloco serves as a regional lingua franca and second language among Filipinos in Northern Luzon, particularly among the Cordilleran (Igorot) ethnolinguistic groups, as well as in parts of Cagayan Valley and some areas of Central Luzon.

As an Austronesian language, Iloco or Ilocano shares linguistic ties with other Philippine languages and is related to languages such as Indonesian, Malay, Tetum, Chamorro, Fijian, Māori, Hawaiian, Samoan, Tahitian, Paiwan, and Malagasy. It is closely related to other Northern Luzon languages and exhibits a degree of mutual intelligibility with Balangao language and certain eastern dialects of Bontoc language. Iloco is also spoken outside of Luzon, including in Mindoro, Palawan, Mindanao, and internationally in Canada, Hawaii and California in the United States, owing to the extensive Ilocano diaspora in the 19th and 20th centuries. About 85% of the Filipinos in Hawaii are Ilocano and the largest Asian ancestry group in Hawaii. In 2012, it was officially recognized as the provincial language of La Union, underscoring its cultural and linguistic significance.

The indigenous peoples of the Cordillera in northern Luzon, Philippines, often referred to by the exonym Igorot people, or more recently, as the Cordilleran peoples, are an ethnic group composed of nine main ethnolinguistic groups whose domains are in the Cordillera Mountain Range, altogether numbering about 1.8 million people in the early 21st century.

Their languages belong to the northern Luzon subgroup of Philippine languages, which in turn belongs to the Austronesian (Malayo-Polynesian) family. A 2014 genetic study has found that the Kankanaey (an Igorot subgroup from Mountain Province), and by extension other indigenous Cordillera groups, descend almost entirely from the ancient Austronesian expansion originating in Taiwan around 3000-2000 BCE