Franglais is a mix of French and English in the same stretch of talk or writing: English words dropped into French sentences, or French words dropped into English, often with a smile or a complaint. The name was coined in French, and French speakers often use it when they feel English is crowding into French — business jargon, ads, internet talk. English speakers use it more loosely for any Franco-English jumble, including tourist French full of English. It is informal and a bit jokey; it is not a real language you can study with a grammar book, and it is not the same as the careful bilingual speech of people who truly speak both languages well. You may also see it for a style that feels half in one language, half in the other, without strict rules.