The Trilingual Siblings: Leo & Louis

Leo, 6, and Louis, 2, are brothers born and raised in Hong Kong. Through naturalistic interactions with their parents, grandparents and domestic helper, both boys had developed comprehension and production skills in Mandarin, Cantonese and English and proudly embraced their identity as a trilingual by age 3. In many important developmental measures, their performance matches standards of monolingual children of these languages.

Leo and Louis’s mother is a linguist dedicated to the study of language acquisition and multilingualism. Leo and Louis have been video-taped regularly and systematically at home since they were babies. The video recordings document how the young boys gradually acquire the three languages through playing, reading and daily routines with their caretakers at home over the years.

A team of researchers have transcribed the conversations in some of the recordings into analyzable text (‘transcripts’) and constructed the Leo Corpus, which has been deposited in CHILDES, the largest child language data exchange platform for open access. You can download the transcripts and audio recordings from Leo Corpus at CHILDES, and know more about the trilingual input and development in this publication.

The Louis Corpus is under construction. This new corpus has a special monthly session recording Louis’s interaction with his brother Leo, in addition to his caretakers. Contact Louis’s mother if you are interested in joining the recording, transcription and/or the analysis of the Louis Corpus.

This page posts additional information about the trilingual siblings and their corpora, which has not been included in CHILDES, but may be interesting to researchers, teachers and parents.

Leo Corpus: 5-min video introduction

Leo: longest utterances in three languages at 2;11

CLAN codes omitted; adjusted for standard orthography

a. Mandarin (3SG = third person singular, D = determiner)
Ta jiu keyi kan hao yuan hao yuan de defang.
3SG then can see very far very far D place
‘Then he can see places far far away.’

b. Cantonese (PAS = passive marker; PERF = perfective; SFP = sentence final particle)
Wui2 m4 wui2 bei2 fung1long6 ceoi1 zo2 heoi3 tin1soeng5 aa1.
will not will PAS storm blow PERF go sky SFP
‘Will it be blown up into the sky by the storm?’

c. English
Thomas is not crying because he’s a big boy too!

Leo: spontaneous use of auxiliary be and progressive –ing at 2;11

Leo producing progressive –ing form (in italic) in a felicitous context at 2;11 (CLAN codes and tags omitted; adjusted for standard orthography; MOT = mother, CHI = child/Leo)

*MOT: Why don’t you get a … get some rest?
*CHI: Okay.
*MOT: Okay.
*CHI: Let me land first, okay?
*MOT: Okay.
*CHI: Vroo!
*CHI: They are having a party!
*MOT: Oh, who’s having a party?
*CHI: The airplane.

Leo: English morphology at 6 years

Leo (6;4) exchanging views with Louis (2;6), trying to locate a missing toy car

*LOU: Is it here?
*LOU: No.
*LEO: I have…I haven’t seen it anywhere.

Leo (6;5) reflecting on his strategies in a sorting task that he had just completed with Louis

LEO: I think in the first place I should have put the greens here. And the reds like, put it in this pillow. Never knew we needed to use these things, all the things on the beds except toys, to put these on. Never knew. Or we could have…but we have things here, here, and here, and here, here, and here, everywhere. Everywhere!