This worrying trend undoubtedly needs to be reversed if the city is to maintain its competitive edge over rival cities such as Singapore and Shanghai.

However, I don't agree with Mr Au's view that English is considerably more important than Putonghua.

Given the fact that Hong Kong is an integral part of China, with Putonghua being the national lingua franca, not to mention the ever-growing business with the mainland and its visitors continuing to flood the city with their oversized suitcases, the language could not be any more important in today's Hong Kong.

The view that Putonghua should be treated as a "dispensable language" may have been relevant 30 years ago, but is certainly not relevant in this day and age, which is why many people all over the world are currently learning the language.

With the ongoing cross-border feud, whether it involves parallel traders, migrants, tourists or business people, tensions between locals and mainlanders have reached boiling point, and this may have hindered the popularity of Putonghua in Hong Kong.

As Mr Au pointed out, other factors include a lack of quality Putonghua teachers in the city, as well as many locals' love affair with Cantonese.

The government should try to promote a more positive image that embraces Putonghua and English in order to give locals more incentive to learn these languages, as well as to find more good-quality Putonghua and English teachers. The overall problem with language skills in Hong Kong applies to English, Putonghua and Cantonese, as these are the main spoken languages in the city.

Ideally Hong Kong citizens should try to be proficient in all three of these languages. There is no room for being monolingual, whether for locals, mainlanders or foreigners living and working in the city.