generation 1.5 /ˌdʒenəreɪʃən ˌwʌn pɔɪnt ˈfaɪv/ BrE AmE noun [uncountable] American English
people born and living in the US, whose parents originally come from a foreign country and have not learnt to speak English properly. Generation 1.5 children are able to speak English well, but talk in the language spoken by their parents when they are at home.