It's not "real" Arabic you're speaking, but rather words that come from Arabic. After Latin and English, Arabic is probably the biggest contributor of words to the Spanish language, and a large portion of English-Spanish cognates (words that the two language share) that don't come from Latin come from Arabic.
The English words you're most likely to think of as Arabic origin are those that start with "al-," words such as "algebra," "Allah," "alkali" and "alchemy," and they exist in Spanish as álgebra, Alá, álcali and alquimia, respectively. But they are far from the only ones. A variety of other types of common words such as "coffee," "zero" and "sugar" (café, cero and azúcar in Spanish) also come from Arabic.
The etymology of English words goes beyond the scope of this article, but the introduction of Arabic words into Spanish began in earnest in the eighth century, although even before then some words of Latin and Greek origin had roots in Arabic. People living in what is now Spain spoke Latin at one time, of course, but over the centuries Spanish and other Romance languages such as French and Italian gradually differentiated themselves. The Latin dialect that eventually became Spanish was highly influenced by the invasion of the Arabic-speaking Moors in 711. For many centuries, Latin/Spanish and Arabic existed side by side, and even today many Spanish place names retain Arabic roots. It wasn't until late in the 15th century that the Moors were expelled, and by then literally thousands of Arabic words had become part of Spanish.
On the next page are some of the most common Arabic-origin Spanish words you'll come across. As you can see, many of the words also are a part of English. Although it is believed that the English words "alfalfa" and "alcove," which originally were Arabic, entered English by way of Spanish (alfalfa and alcoba), most Arabic words in English probably entered English by other routes. Not all possible English translations of the Spanish words are listed.