Language of Nicaragua
The official language of Nicaragua, according to the constitution, is Spanish and it is spoken by 95% of the population. So, if you are traveling to Nicaragua, you should brush up on your Spanish and bring a Spanish dictionary. However, Nicaraguan Spanish is a Central American style dialect with its own unique attributes. So, even if you have experience with other Central American Spanish dialects, it may take a little bit of work to learn the intricacies of the language. But, as long as you are fluent in Spanish, you shouldn't have any trouble getting around Nicaragua and either understanding the language or being understood.
There are several minor indigenous languages used within Nicaragua, however they are used by a very small percentage of the population and can mostly only be found in small remote villages. The indigenous languages include Miskito, Sumo, Rama, Garifuna, and Criollo.