French language
French pronunciation, more so than other Romance languages, became radically different from Latin. After the Roman Empire fell and Germanic peoples swarmed the countryside, Vulgar Latin was changing quickly. In medieval France it changed into two dialects or languages: langue d'oc and langue d'oïl. They both mean "language of yes", because oc was the word for "yes" in the south, and oïl meant "yes" in the north.  Today, the word for yes in French is oui, pronounced like "we".