This is an on-going longitudinal study of three simultaneous bilinguals in a one parent-one language environment. Bi-weekly audio recordings in subjects' homes were transcribed in the CHILDES format.

Subjects		Native language of parents		Age span during longitudinal study
Name	Date of Birth	Mother	Father
Kathryn	1.92	English	Cantonese	2;10 - 4;6
Timothy	5.93	Cantonese	English	1;6 - 3;6
Llewellyn	6.93	Cantonese	English	1;6 - 3;6

The background of the three bilingual children

All three children have grown up in bilingual families in Hong Kong, with one parent speaking Cantonese and the other English. Each of the parents knows the other's language to some extent. The community language is Cantonese.

• Timmy

  Both parents are professional linguists. He has an English-speaking Filipina helper. From age 2;4 to 3;1 he attended a bilingual international kindergarten. He is often cared for by his maternal grandmother who speaks Chiu Chow as well as Cantonese, and he likes to show off the few phrases of Chiu Chow that he knows:
  Lei5 sik6-zo2, lei5 ziah-zo2 la!

  He also code-mixes as in:
  "You see the time, gau3 zung1 la3!"
  "Outside have a computer, dim2 gaai2 m4 get out a?" (3;1)

  Quotes:
  "I like Coke, I like Perrier, I like everything" (2;7)
  "Dark have witch outside, cannot go out, and raining" (3;0)
  "Ma1mi4, lei5 heoi3 ji1 jyun2 saang1 do1 go3 mui4mui2 la1!" (3;1)

• Llewellyn

  This child has an elder brother who was linguistically precocious, fluent in both languages but using rather more English. His father is a professional linguist and his mother an accountant. He has two Filipina helpers.

  The child had already started to attend an English-speaking playgroup when data collection started.

• Kathryn

  Kathryn's father is a surgeon and her mother a housewife. She has two elder brothers. The child was enrolled in a Chinese kindergarten during the whole period of data collection. She was taken care of by her mother and occasionally by her grandmother.