Actually, I am not a research linguist. The main difference in speech in Paraguay is that nearly all Paraguayans (those born there, anyway) are bilingual: they speak Spanish and a local Indian language called Guarani (Guarani is also the name of the local money). I expected Paraguayans to be far more Indian in appearance than they are: there are some people who have Indian features, but many, many fewer than in Mexico and Central America. Paraguayans look more Spanish, Italian or Portuguese, mostly. Of course there are people from everywhere in Paraguay. I did not see any Black people, though. There are tribal Indians still living in the Chaco to the West of the country.
I wanted to visit Paraguay because of several novels I had read and several other books that were very interesting about the two wars Paraguay has fought: the Tripartite war, in which Argentina, Brazil and Uriguay all attacked Paraguay, a war which lasted five years until 1971, and ended when Francisco Solano Lopez. the obese president of Paraguay was killed with a lance and proclaimed "I die with my country!", and the Chaco War with Bolivia, 1932-36. The peace treaty of the first war was mediated by US President Rutherford B. Hayes and awarded a goodly share of the Chaco to Paraguay, causing them to name a province as well as a town (Villa Hayes) after him.
Also, I once had friend and colleague, a science teacher born in Germany who fought in WWII in the Wermacht named Hank Schapp, who dreamed of visiting Paraguay, since so many Germans went there. Online I met another German, Peter Gardner, who was born in E. Germany near Dresden, and went to an agricultural school, and about 12 years ago got tired of the winters and migrated to Paraguay, where he has a small 33ha. farm and provides lodging for tourists and sells milk, honey and several other products in his own small store in Concepcion. He married a Paraguayan woman and has three children./ You can see his farm online at
http://www.paraguay.ch. He collects local animals, and when I was there had a bunch of parrots, a capybara and a peccary. So I went to Montevideo, crossed Uruguay in the dead of night, took a ferry across the Uruguay river, visited the huge Yacyreta Dam across the wide Parana, and went by bus through Encarnacion and Asuncion on to Concepcion, where I spent about nine days on Peter's farm. Room and board were a reasonable $100,000 Guaranis a day, which is $25 US, plus beer, which is an excellent brew named Pilsner and comes in 1 liter returnable bottles.