Singlish is the uncouth version of English used almost exclusively in informal speaking in this country. The amalgamation of English and several locally-used languages and dialects, such as Mandarin Chinese, Malay and the Hokkien, Teochew and Cantonese dialects.
Conversation is made through the use of broken English, code-switching and interjections. The “language” came from the need to use English as lingua franca across four national races during and after British rule. Lack of proper education was common in the old days and people had to make do, eventually corrupting the language, but not quite in a bad way.
It’s not easy to explain, I guess. It’s a native thing, like how Cockney rhyming slang exists in the UK.