Identification. The Tagalog language is the basis of Pilipino, the national language of the Republic of the Philippines since 1937, and has been taught from the first grade throughout the archipelago since the early 1950s. Thus most Filipinos (60-70 million) under the age of 50 speak, read, and write Tagalog as at least a second language, while some 10 to 15 percent (perhaps 10 million) have learned it as their first language. This article deals only with the latter group. The usual derivation of the name "Tagalog" is from taga ilog, meaning "inhabitants of the river."
Location. The Tagalog-speaking area is oriented toward Manila Bay and is concentrated mostly within SO to 320 kilometers of the megalopolis of Manila on the island of Luzon. It lies within the Tropic of Cancer from 10° to l6°N and from 119° to 123° E. It consists of the provinces of Bataan, Bulacan, Rizal, Cavite, Batangas, Laguna, Quezon, parts of Nueva Ecija and Camarines Norte, Marinduque, Polillio, parts of Mindoro and Palawan, and many smaller islands. The topography includes mountains up to 2,000 meters and uplands with tropical rain forest cover as well as a wide range of lowland coastal and inland environments. Monsoon seasons vary from location to location, and there are dramatic differences in annual rainfall (152 to 457 centimeters) and length of wet and dry periods. Typhoons, earthquakes, volcanic eruptions, droughts, floods, and malarial vectors form ever-present threats for the people of the area.
Demography. As of 1991 the population in this "heartland" of the Tagalog area (Katagalugan) was over 10.9 million in approximately 23,920 square kilometers (325 persons per square kilometer). Probably another 100,000 people whose first language is Tagalog live elsewhere in the Philippines and abroad.
Linguistic Affiliation. Tagalog belongs to the Malayan Branch of the Austronesian Phylum. The dialect of Tagalog spoken in Manila is often called "Taglish" because of the high percentage of American English words.