English borrows a lot of good words and phrases from other languages. Typically, those words are used in some way that is at least remotely close to the original use. While these words and phrases can change when taken into English, often these changes are inadvertent, irregular, and make the phrase make no sense. Here's how to use these phrases correctly.

• It's "mano a mano" not "mano y mano". In this case, the "a" means "vs." while the "y" just means "and". If you say "mano y mano" it makes no sense at all.
• "Via" is often misused. A person who was born in Buffalo, lived in Boise, and now is in Birmingham, if asked where they're from, would correctly answer "Buffalo, via Boise" rather than the more common, and incorrect, "Boise, via Buffalo". "Via" in this case basically means "through".
• "Cajones" means "chest of drawers". "Cojones" means "balls." This is hard to keep track of because most American accents pronounce the two about the same, but, in print, it's better to say what you mean.