Spanish is the most widely spoken Romance language in terms of the number of speakers and the number of countries which claim it as the official language. From its origins in Spain, the Spanish language was carried to the new world by trade, conquest, and colonization. Today, it is spoken throughout much of Central and South America in addition to Spain. There are also many people who choose to learn Spanish as a second language.
Much of Spanish vocabulary stems from Latin, which was introduced to the Iberian peninsula in the 3rd century during the Roman conquest as a dialect, Castilian. During the Christian reconquest of the 15th century, all the kingdoms of Spain were united and the language of Castile became the dominant dialect. Castilian Spanish is spoken in Spain today. Castilian Spanish and Latin American Spanish differ from region to region. Latin American Spanish, in particular, has evolved since colonization. For example, peach is melocotón in Spain and durazno in Latin America. One notable difference is the inclusion of words from the indigenous languages of Latin America into modern Spanish vocabulary.
Many of the words that begin with "f" in other Romance languages begin with an "h" in Spanish (hilo, thread; hijo, son). Another distinction in the Spanish language is the Moorish influence. Many Spanish vocabulary words beginning with "al-" are of Moorish descent (alfombra, rug; alfiler, pin; almohada, pillow).
English words that come from Spanish vocabulary include cargo, siesta, hacienda, patio, armada, canyon, plaza, rodeo, adobe, vanilla, tornado and embargo.
As you learn Spanish, you will learn two ways to address someone, familiar and formal. The familiar form of you is tú and verbs used with tú are conjugated in the 2nd person. The formal form of you is usted and verbs used with usted are conjugated in the 3rd person. The familiar form is used with friends or with people who are younger you. The formal form is used when you speak Spanish with elders or people you don't know.
One marked difference between Castilian Spanish and Latin American Spanish is the use of vosotros and ustedes. Vosotros, used only in Spain, is the informal plural form of you and the corresponding verb is conjugated in the 2nd person plural. Ustedes is the formal, plural form of you. However, in Latin America, ustedes is used for both the formal and informal address for 2nd person plural but the corresponding verb is conjugated in the 3rd person plural form. For example, "Vosotros estáis felices " and "Ustedes están felices" (You are happy) mean the exact same thing, but the former would only be used in Spain.