LKY has admitted that it is not possible to master two languages at the same level. That is the fact in life.
The video just confirms it.
LKY speech at the official opening of the Singapore Center for Chinese Language on 18 November 2009
“We started the wrong way. We insisted on ting xie (listening), mo xie (dictation) – madness! We had teachers who were teaching in completely-Chinese schools. And they did not want to use any English to teach English-speaking children Chinese and that turned them off completely.”
“At first I thought, you can master two languages. Maybe different intelligence, you master it at different levels.”
“Nobody can master two languages at the same level. If (you think) you can, you’re deceiving yourself. My daughter is a neurologist, and late in my life she told me language ability and intelligence are two different things."
Successive generations of students paid a heavy price, because of my ignorance, by my insistence on bilingualism.”