I feel that there is nothing wrong in being the master of just one language; and that while there *are* advantages in being "multi-lingual", IF one is master of none, then there are also disadvantages too.
Increasingly I find that in work, people who have a weak grasp of English, who cannot write to save their lives, hamper productivity and creativity. How can a person innovate if he can’t express in complex/abstract/poetic/metaphysical terms what he’s trying to invent? I have realized with increasing worry that project documents are often being dumbed down to the point of irrelevance because people don’t know how to articulate complex ideas.
Have you ever watched two people with poor English argue a complex issue in English? (eg. it could be a Malay with a Chinese). You will get what I mean.
Coming back to parenthood, have you ever torn your hair in frustration trying to answer an innocent question from your child which involves complex reasoning/words? You will see then how important it is to be able to understand the words of someone who is linguistically more capable.
So anyway, it may be great for international business and this trendy thing called "globalization", but I feel that while many expound on the merits of being multi-lingual, they forget that they are master of no language. This means everything they say is half-baked. The fact is: many Singaporeans may be "multi-lingual" but they are certainly NOT multi/LINGUISTS. A truly bilingual person would be one who has mastered two languages, for example.
Face the fact: in Singapore, PRCs laugh at our Chinese, while Americans laugh at our English. What does this tell you?
I make no excuses for the fact that my Mandarin is weak (which I regret a little) – for my English is excellent. Employers continue to underrate this, even as standards of English in Singapore continue to degenerate. And yet, I am always the target of pleas for help in vetting documents, cleaning up language, improving resumes, articulating design ideas, etc. My Mandarin has improved with exposure, I also speak decent Hokkien, and I’m learning Japanese. I’m master of none of these languages, but I have at least mastered English.
My point – if you ask me for my recommendation, it would be that, go ahead and let your child speak/learn as many languages as he wishes, but please ensure she is at least master of one.