Tagalog is an Austronesian language spoken as a first language by the Tagalog ethnic group, which constitutes about a quarter of the population in the Philippines. It is also used as a second language by the majority of Filipinos.
According to Wikipedia, the term "Tagalog" might come from the endonym Taga-Ilog ("river dweller"), which combines tagá- ("native of" or "from") and Ilog ("river"), or possibly from Taga-Alog, derived from Alog ("pool of water in the lowlands", "rice or vegetable plantation"). Linguists like David Zorc and Robert Blust suggest that the Tagalogs and other Central Philippine ethno-linguistic groups may have originated in Northeastern Mindanao or the Eastern Visayas.
Classification of Tagalog Language
Tagalog differs from its Central Philippine counterparts with its treatment of the Proto-Philippine schwa vowel *ə. In most Bikol and Visayan languages, this sound merged with /u/ and [o]. In Tagalog, it has merged with /i/.