The SIL group is using a new term I think should become more common – the macrolanguage A macrolanguage is basically a set of related languages that share a common “identity” even though speakers can’t normally understand each other.
The most famous macrolanguage is probably Chinese. It is fairly well-known that a speaker from Beijing speaking Mandarin Chinese will often have difficulty understanding a Cantonese Chinese speaker from Hong Kong…unless someone has taken a formal class in the other form. Normally, these are called Chinese dialects but the differences are so great that linguists do classify them as separate languages. Interestingly, each of these languages can also have regional variations (many regional variations of Mandarin Chinese are found in Northern China).
Chinese is not alone by the way. Other macrolanguages include Arabic, Cree, Hmong, Quechua (as spoken in the Incan Empire), and Norweigian. I suspect that you could thrown in some other candidates like German and Italian.
As you can imagine, I definitely prefer the term macrolanguage over dialect for Chinese because it removes the confusion of regional dialects where everyone can understand each other (e.g. most English dialects) and those which are really separate languages (e.g. Chinese “dialects”). The term macrolanguage also acknowledges the strong cultural link between the speakers of the related languages.
I really hope this term takes hold…because I really think it will simplify other discussions about language (like language code). After all, it was just this year that a language technology guru claimed that English had no “true dialects.” I think he meant to say that English hasn’t reached macrolanguage status yet.