This question is fun for me to answer as my family is involved in this very diversity. The biggest majority of the Hispanic people in this country are from Mexico as it has a border with the U.S. and a great influx of people seeking a better life for their families. Now, however, more people from Central and South America have begun to live here and contribute their culture and customs to the US. I find the biggest influences in accents, food, music and drinks. For example, my son-in-law is from Argentina where a different Spanish with accent and word differences is spoken, and the grass fed beef they eat is usually accompanied by chimi churri where every recipe is different. They have a great Italian influence in their food evidenced by the home made gnocchi served when we visited. I have an Argentine exchange son who taught us about the modern Argentina with its shopping and dancing. My Bolivian exchange son visits and brings with him the food and pineapple tea I love. Bolivia's people are divided between those of the highland country and the big city of Santa Cruz de la Sierra in the tropical part. More prominent in the eastern U.S. they have brought their food such as peanut soup and their love of barbecue. Their meals are eaten much more slowly making it a social occasion. The Latin music is part of the fabric of the US with many clubs having nights devoted to different Latin dances or music and shows up especially in Zumba, the exercise craze. Many of the Ecuadorian people have brought their music to the street musicians as well. Brasil and its people have also added to the diversity, especially in music and food. Caipirina made with Cachaca, a Brazilian specialty, has become more common as has Feijoada, the national dish. I love the diversity of this country and wish I spoke Spanish to better participate in the cultural additions people make to our culture here.
The 1,900-mile long border separating the United States from Mexico has been an avenue through which millions of Mexican immigrants have transited over the past one hundred years, giving the southwestern U.S. in particular a decidedly Hispanic flavor. In addition, U.S. control over the island-nation of Puerto Rico, seized from the Spanish during the Spanish-American War of 1898, has provided many Puerto Rican nationals an entry into the United States, with heavy concentrations in New York and surrounding environs. Similarly, very large Cuban-American populations, especially in Florida and New Jersey, are a product of waves of immigration resulting from communist control of that island-nation and the vast economic disparity between Cuba and the U.S. These three Hispanic ethnicities, for many years, were the most visible symbol of Hispanic culture in the United States. They are not, however, the sole representation of such cultures. Over the years, especially since the civil wars and other political strife that dominated Central America during the 1980s, immigration from Latin America has been represented also by refugees and migrants from El Salvador and Guatemala, with smaller numbers from Honduras and Nicaragua. These immigrants, represented both by that region’s myriad indigenous tribes, such as the Mayan of Guatemala and southern Mexico, and the more ethnically diverse mixed-race tribes of Nicaragua, El Salvador and elsewhere, have made their own contributions to American culture, especially in the areas of cuisine, sports, art, and dance. The prevalence of professional baseball players in the United States from Latin America and the Caribbean, including the Dominican Republic, Venezuela, and Cuba, has injected an unprecedented level of ethnic diversity into what was originally a uniquely American endeavor. Cuban-American populations in Florida and New Jersey have influenced those states’ politics, especially with regard to the politically-sensitive issue of U.S.-Cuba relations, which in turn has influence national policy and perspectives. In short, immigration from throughout the Americas has contributed greatly to the diversity of the Hispanic influence in the United States. Economically-motivated immigration from South America, combined with flight from autocratic regimes, has been similarly, if to lesser degrees, influential on Hispanic cultures in the United States. Migrants from perpetually-strife-torn Colombia, for instance, have increased the level of ethnic and cultural diversity in Florida (as did the enormous influx of Haitian immigrants during the late 1980s), and Central American influences are felt throughout Los Angeles County, with Salvadoran communities competing with Guatemalan communities for social influence.
Large influxes of immigrants from Central America and, to a much lesser extent, from South America (where economies are much larger and more technologically advanced) have definitely altered the complexion of Hispanic culture in the United States, which was born of immigrant experiences in the first place.