* Tagalog is a language, not an ethnicity: While there are people who identify as "Tagalog," it's more accurate to say they are Filipino, as that's the national identity.
* Tagalog is the national language of the Philippines: It's spoken by a majority of Filipinos, but not everyone. Other major languages in the Philippines include Cebuano, Ilocano, and Hiligaynon.
So, to answer your question:
* Tagalog speakers live all over the Philippines, particularly in the central and southern regions.
* Outside the Philippines, Tagalog speakers are found in communities of Filipino immigrants, mainly in the United States, Canada, Australia, and other countries with large Filipino populations.
It's important to be mindful of the nuances in language and identity when talking about Filipino people and their culture.