I live in Orlando, but get down to Miami every now and then. I would not consider Miami "like a third world country." That implies more than just a lot of Spanish speaking people--it implies poverty, and while they do have poverty in Miami, it's not like in a third world country. It's like every other large American city. They've got poverty, but they've got riches too. You have to go to the bad neighborhoods to see the poverty.
'Depends on where you lived.
Where I reluctantly moved to (after 40 years in South Miami), we had two kinds of "sound trucks": One played salsa music at full bass through speakers mounted in a large panel van. (Although sometimes huge speakers were placed stationary on downtown sidewalks, vibrating every body who happened to drive by).
The other had two large loudspeakers and announced Cuban politics in Spanish while driving through the neighborhood. I'm sooo glad I left. Geez—twenty years ago, announcements in Sears stores were made in Spanish!