I'm not the grandparent but: Arabic is highly diglossic: in any given area, people use a standard written language called Modern Standard Arabic (used in speec

I'm not the grandparent but: Arabic is highly diglossic: in any given area, people use a standard written language called Modern Standard Arabic (used in speech only in certain formal situations) and a local spoke language ("vernacular") used in everyday life. They differ greatly in terms of grammar, pronunciation and vocabulary. Note that vernacular isn't mere slang: it's one's native language. Also, the vernaculars form a sort of dialect continuum: a Iraqi might have little problem understanding a Syrian from a nearby area, and Syrians might have little trouble understanding Palestinians, and so on, but Iraqi and Moroccan Arabic have little mutual intelligibility. Neither phenomenon is unique to Arabic. Some Americans speak, say, African American Vernacular English but can also use "standard" American English; of course the difference isn't that big in this case. Brazilian Portuguese is another case of diglossia: the written language has multiple verb tenses and conjugations that aren't used in spoken language, for example. Dialect continuums also happen in other places, e.g. the Getman speaking countries. But Arabic is an especially extreme and interesting case (subjectively speaking).