Is Castilian Different than Spanish?

A: The Oxford English Dictionary differentiates Spanish and Castilian, noting that Castilian is the Spanish spoken in Spain. But español and castellano in Spanish are synonymous. Castellano or español is the language of Spain and its former colonial territories in America, most of which became independent republics in the 19th century. Notice that I wrote español, without a capital E. Languages, nationalities, days of the week and months are not capitalized in Spanish. We say inglés for English, francés for French, polaco for Polish, ruso for Russian, farsi for Iranian and vietnamita for Vietnamese.

Oscar Wilde said England and the United States were two countries separated by the same language. Spain and Latin America (including Hispanics in the US) are two worlds joined by one language. Formal Spanish is the same everywhere. There are colloquial differences, of course. Los argentinos y los uruguayos pronounce the ll, the y the g as English speakers pronounce the sh in she. Some bolivianos and ecuatorianos pronounce the ll as the l in Leonor. Most other Spanish-speakers pronounce the ll as the y in yo-yo. Latin Americans pronounce the c, s and z as the English s in Sam, but in Spain the z sounds more like the th in thanks. In Latin America both v and b sound identical to the English b in boy.