The ranchera is a song form composed of an instrumental intro, verse and refrain, instrumental break, verse and refrain, and then a tag ending. They’re mostly love songs, either romantic or patriotic, and they are usually played with guitars and horns.
Norteña (northern) songs aren’t structured as rigidly as rancheras, but they have their own distinguishing characteristics. The bands that play them are composed of an accordion, a bajo sexto (12-string Mexican guitar), a bass guitar, and drums. It carries a large influence from polka, of all things, and is extremely popular in Mexico.
Cumbia is a style that originated in Columbia, but is popular all over South and Central America. I’m not familiar enough with it to really elaborate, but I’m sure someone around here is.
There are other styles of Central and South American music that I’m not really familiar with (like mariachi), and in addition to those styles, in the Caribbean, we have reggaeton, merengue, salsa and many others. On top of that, there are styles of música latina that coincide more or less with American pop, jazz, rock, rap, hip-hop, and any other genre you can think of.
Hie thee to allmusic’s Latin category and explore.