For example, Chinese is a macrolanguage encompassing many languages that are not mutually intelligible, but the languages "Standard German", "Bavarian German", and other closely related languages do not form a macrolanguage, despite being more mutually intelligible. Other examples include Tajiki not being part of the Persian macrolanguage despite sharing much lexicon, and Urdu and Hindi not forming a macrolanguage despite forming a mutually intelligible dialect continuum. Even all dialects of Hindi are considered as separate languages. Basically, ISO 639-2 and ISO 639-3 use different criteria for dividing language varieties into languages, 639-2 uses shared writing systems and literature more whereas 639-3 focuses on mutual intelligibility and shared lexicon. The macrolanguages exist within the ISO 639-3 code set to make mapping between the two sets easier.