Hong Kong's language mix

I'm in Hong Kong, and I can't help but remember the article by Ho Judy Wong Yee in the Australian Review of Applied Linguistics (2008), which had this abstract:

"China resumed its sovereignty over Hong Kong in 1997. Since then drastic changes in this former British colony have occurred. One of these changes is a shift in language policy, from bilingualism (Cantonese and English) to trilingualism (Cantonese, English and Putonghua). The present study is aimed at investigating tertiary students' use of Cantonese, English and Putonghua on a daily basis, analysing the roles and functions of each language and discussing how these may impact on language policy and language education. Research instruments included 52 students' language diaries and written analyses, 51 hours of audio-recordings of verbal exchanges, and focus group semi-structured interviews. Results show that the students' speech repertoire mainly consists of two languages: Cantonese and English and their various mixes. Cantonese is used to ensure understanding, consolidate solidarity and maintain social cohesion. The English-Cantonese mix has become a more powerful identity marker for educated people in Hong Kong than pure Cantonese. English and its supplement with Cantonese are often used in the domain of education. The majority of students seldom use Putonghua in everyday life, but there is a strong instrumental motivation to learn it. Measures are suggested to facilitate a more successful move from bilingualism to trilingualism."

The article confirms what the late linguist Andrew Gonzalez FSC kept saying, despite his having been instrumental in institutionalizing bilingualism in the educational system of the Philippines: "You cannot legislate language."

The other evening, I had dinner with friends who exemplify the multilingual character of Hong Kong society. One was born in Brazil, grew up speaking Chinese and Portuguese (Brazilian), and now speaks the English that she first learned in school. Another was born in the Philippines, grew up speaking Spanish at home, learned Filipino from her playmates, learned French when she lived in France and English when she lived in the US, and now speaks mainly English in Hong Kong.

If most readers are multilingual, why are writers still writing for imagined monolingual audiences? Is the idea of writing a text only in one language a product of language legislation? Is there an unwritten law that we should write a text only in one language? Just as we cannot legislate or limit language, we cannot and should not limit writers to writing in only one language while their readers speak in more than one language.