A frequent mistake that Spanish learners make is to assume that when they see a Spanish word that looks like an English word, the two words have the same meaning.  There are numerous false cognates between English and Spanish, and it helps to make a special note of these when they show up on a vocabulary list.  Assistir may look like “assist”, but really means “attend”.  Actualmente may look like “actually”, but really means “presently”.  Probar is similar to “prove”, but actually means “try”.  Often, these words have similar roots, but evolved differently to have varied meanings over the centuries.

Check out this extensive list of false cognates: http://spanish.about.com/cs/vocabulary/a/obviouswrong.htm

My favorite false cognate funny….

When you clean your house, you always vacunar la carpeta, right?  Sounds right to our English-speaking ears, but in Spanish that means vaccinate the folder!