A lot of people will say they do not know their native language, and feign disappointment at this fact.
'Oh, yknow I can't speak a word of Indian (sic), and it's supposed to be my ... language. I wish I could, it's kinda sad that I can't' (when I'm so cool saying this)
This is different than saying they're not from a particular place (when they really are). Here they probably don't like being associated with their hometown/region.
Like 'I'm from NYC' is better than saying 'I'm from Jersey City'. Or in India where so many quickly proclaim 'I'm from Bombay', when they're actually native back of beyonders.
Also, they can't say they regret not being from Jersey City.