This book presents multilingualism as a social phenomenon, which arises when speakers of a different language move to a new society and learn to speak the dominant language of the society. It offers case studies of Hokkien migrating families when they encounter new languages in Burma, Macao and San Francisco, showing how a family changes across generations from monolingual to bilingual/multilingual and back to monolingual. In the process language shift occurs as a result of transitional bilingualism. The dynamic status of Hokkien is also attested at the societal level in Singapore, Taiwan and south Fujian, the homeland of Hokkien.