We had always wanted our children to grow up bilingual. Both my husband and I were children of immigrants and grew up in London with two languages and two cultures. He went on to a degree in modern languages and I accumulated fluency in another four languages as I worked my way around the world. We made a living out of being multilingual.
Our daughter did learn Cantonese but at a cost - she felt overburdened by the work when all she wanted to do was talk and play. She had to struggle and was clearly unhappy.
We looked for an international school. The "British" schools were run by the English Schools Foundation (ESF). They offered an excellent education but were blinkered in one respect. Despite the approaching handover to Chinese rule, Chinese was taught only as an "extra-curricular" activity, mostly for children of mixed parentage.
For the Chinese, English was the passport to the best jobs and to emigration to Canada, Australia, Britain and the United States. Even French would notch up more immigration points for a coveted Canadian visa than fluent Mandarin.
The Canadian International School taught Cantonese as a first foreign language from the age of six, alongside the English-medium curriculum. It was favoured by "returnees" (who left Hong Kong in search of passports before the handover, then returned), mixed couples and a few like us. We enrolled our daughter.
What astonished us was how quickly language can fade with disuse. Spoken only during one period a day, her Cantonese quickly began to slide. She even refused to speak to our caretaker with whom she would chatter on a year before.
When we moved to Germany, my daughter was seven and my son five (a late talker, we did not try the Chinese experiment on him). We sent them to a "Europe School" where children learn their mother tongue (English or German) from native teachers but do some subjects in English and others in German. By the age of 10, French is taught every day.
Such schools are so popular that entry for Germans is by lottery, while there is a shortage of British applicants - many prefer an international school where German is taught as a foreign language three times a week.
Germans are generally sad that few in Britain learn the language of Goethe but they take it as a sign of their own decline. "I suppose we Germans would not be interested in becoming fluent in Norwegian either," said one.
It's not just about insular Britons, but the economic power of a language. The Belgians have a joke: you need Flemish to apply for a job, French to get it (connections!) and English to do it. For Germans, English is a necessity. For Britons, German (or Chinese) is an optional extra.
And for all the language learning in German schools, the German publishing company Springer Verlag recently preferred to hire British graduates with their poorer language skills and bring them to Berlin because their German staff (fluent in English) refused to move from southern Germany.
"The English staff are more flexible, know more about the world and can get on with people from everywhere," a Springer manager told me.
After three years, my daughter speaks German with the fluency and accent of a native speaker, although her written grammar leaves something to be desired. My son, now nine, is haltingly fluent in ungrammatical German. For him, it has been traumatic. The school provided no support whatever when he had language difficulties.
Recently, my daughter visited Hong Kong. We wondered if her Chinese would "come back". It did not. But she said "maybe I can study Chinese when I'm older, it'll be easy because I've done it before".
My husband and I exchanged gentle, triumphant smiles.
Yojana Sharma is the TES's Germany correspondent