Spanish or Castilian is a Romance language in the Ibero-Romance group that evolved from several languages in the northern fringes of the Iberian Peninsula during the 10th century, which had gradually spread through the Kingdom of Castile, becoming the foremost language for government and trade in the Spanish Empire.
Latin was the basic foundation of the Spanish Language. And it had been introduces to the Iberian Peninsula by Romans during the Second Punic War around the time of 210 BC. During the time of the 5th century, Hispania was invaded by Germanic Vandals, Alans, Visgoths, and Suevi. Which this had resulted in numerous dialects of Vulgar Latin.
Modern Spanish developed with the Readjustment of the Consonants that had began in the 15th century. This language continues to adapt foreign words from a variety of different languages. As well as developing new words. As of 2010, 329 - 358 MILLION people speak Spanish as a native language and a total of 417 MILLION people speak it worldwide. It is the second most natively-spoken language in the world, after Mandarin Chinese. Mexico is the one that actually holds the largest population of Spanish speakers. Which is one of the six OFFICAL languages of the United States.