It struck me that I needed to give him an answer about how words invention or history of literacy/ writing. I thought about this when I was 20. He is just 6! Luckily he added 'Singapore' so I explained in the Singapore's context first. I started with Sir Stamford Raffles, how he introduced free trading and opened schools to educate teachers to share more word knowledge.
Of course I am going to share with him the long long time ago started 30,000 years ago from Egyptian culture. The recent Mummy's exhibition will help him greatly and this website - http://www.historian.net/hxwrite.htm