What language seem to dominate the nations south of US?

It's impossible to say that one language *dominates* the nations south of the US because the region is incredibly diverse, with a wide range of languages spoken.

Here's a breakdown of some of the most prevalent languages, keeping in mind that this is just a glimpse:

* Spanish: This is the dominant language in many countries south of the US, including Mexico, Central America, and most of South America.

* Portuguese: Spoken in Brazil, the largest country in South America.

* French: Official language in Haiti and parts of French Guiana.

* English: Spoken in Belize and several Caribbean islands, due to historical colonial ties.

* Indigenous languages: A vast number of indigenous languages are spoken across the region, each with varying degrees of prevalence and vitality.

* Other languages: Depending on the specific country, you might find other languages like Dutch (Suriname), Quechua (Peru, Bolivia), Aymara (Bolivia, Peru), Guarani (Paraguay), and many others.

Therefore, there's no single language that "dominates" the nations south of the US. It's a diverse region with a rich linguistic landscape.