The word which is mispronounced nearly always and by people who should know better is "forte" when used as someones strong point. It is pronounced "fort", not for-tay which is a musical term.
"For-tay" is also proper for the strong part of a sword, as opposed to the foible ("Foy-bull"). I would consider it proper pronunciation for noting the strengths and weaknesses of people, as the terms derive from swordplay.