 The Hong Kong Bilingual Child Language Corpus, which is reported in 2005 as the world's largest video-linked database of children becoming bilingual, created by Matthews and Yip, features 170 hours of audio and video files of four families raising their children bilingually in Cantonese and English.The project, which includes transcripts and searchable video and audio segments, took 10 years to compile.This database has already been the data source for several undergraduate and graduate dissertations in Hong Kong, and it is the basis of a book, "The Bilingual Child", written by Yip and Matthews and published by Cambridge University Press in 2007, which received the Leonard Bloomfield Book Award from the Linguistic Society of America in 2009.