English as a first language is just propaganda - a legacy from Singapore's dead dictator's regime.
No one in Singapore speaks English properly, nor are they able to think in English properly, because English is the first language of not one of Singapore's three main ethnic groups. The Chinese speak Chinese as their first language (or a dialect of same), the Malays Malay and the Indians Tamil. English is the first language of not one of these groups.
English is a working language of the country, along with Mandarin, since the government has successfully killed off the county's national language from being a functioning working language of the state.
To be a first language, English has to be the language of thought. Put a Singaporean in an English speaking country and he will struggle to articulate himself. He may try to fake an American/Australian/British (delete as appropriate) accent, but this can only last so long.
Old Harry lied to Singaporeans. He installed Malay as the country's national language but made it worthless, because all government communication is presented in four languages.
If English were the first language of the people of Singapore, it would be unnecessary to distribute all comms in four languages.
The linguistics of Singapore are as fragmented as its people. Every ethnic group has their first language and they speak to another ethnic group in English - every Singaporean's second language.