If you are referring to people from Spain, the right word is españoles. But if your are referring to hispanics, the right word is hispanos. People who speak Spanish are gente de habla hispana or...
"Do you speak Spanish" would come in two forms, depending on to whom you are speaking. For a formal tone, one would use "¿Habla usted español?". Informally, it would be "¿Hablas español?"