Spanish (español) is a Romance language named for its origins as the native tongue of a large proportion of the inhabitants of Spain. It is also named Castilian (castellano  listen (help·info)) after the Spanish region of Castile where it originated. Spanish is the second most natively spoken language in the world, after Mandarin Chinese.

In 1999 there were, according to Ethnologue, 358 million people speaking Spanish as a native language and a total of 417 million speakers worldwide. Currently these figures are up to 400 and 500 million people respectively. Mexico contains the largest population of Spanish speakers. Spanish is one of the six official languages of the United Nations, and is used as an official language by the European Union and Mercosur.

Spanish is a part of the Ibero-Romance group that evolved from several dialects of spoken Latin in central-northern Iberia around the ninth century and gradually spread with the expansion of the Kingdom of Castile (present northern Spain) into central and southern Iberia during the later Middle Ages. Early in its history, the Spanish vocabulary was enriched by its contact with Basque and Arabic, and the language continues to adopt foreign words from a variety of other languages, as well as developing new words. Spanish was taken most notably to the Americas as well as to Africa and Asia-Pacific with the expansion of the Spanish Empire between the fifteenth and nineteenth centuries, where it became the most important language for government and trade.

Michel Thomas (born Moniek (Moshe) Kroskof, February 3, 1914 – January 8, 2005) was a polyglot linguist, language teacher, and decorated war veteran. He survived imprisonment in several different Nazi concentration camps after serving in the Maquis (World War II) of the French Resistance and worked with the U.S. Army Counter Intelligence Corps during World War II. After the war, Thomas emigrated to the United States, where he developed a language-teaching system known as the Michel Thomas Method. In 2004 he was awarded the Silver Star by the U.S. Army.

Thomas was born in Łódź, Poland, to a wealthy Jewish family who owned textile factories. When he was seven years old, his parents sent him to Breslau, Germany (now Wrocław, Poland), where he fit in comfortably. The rise of the Nazis drove him to leave for the University of Bordeaux in France in 1933, and subsequently the Sorbonne and the University of Vienna.