Ask Mr. Know-It-All: Why does Cantonese pronunciation vary? Is it "nei" or "lei"?

Dear Mr. Know-It-All,
Can you help me with some pronunciation problems? Is “you” meant to be nei or lei? I hear native speakers saying both! – Tone Deaf

Your ears don’t deceive you, Tone Deaf. Cantonese, with its seven (or nine) tones, is tricky enough to the untrained ear without pronunciation varying wildly. But that difference you’re hearing is what’s colloquially called laan yum: “lazy tones.”

Laan yum refers to a shifting in the pronunciation of certain syllables, among those whom the older generations are happy to call the lazy youth of today. The most identifiable of these shifts are a move from “n” to “l,” from “gw” to a straightforward “g,” and when the “ng” sound turns into “m” or “n.”

How does it work? Well, for example, the sentence: 你好，我識講廣東話 means “Hello, I can speak Cantonese.” It’s pronounced “Nei ho, ngor sik gong gwong dong wah.”

With lazy tones, it becomes: “Lei ho, or sik gong gong dong wah.”

Or take ngau nai, cow’s milk: it’s au lai to the lazy-toned. The very name of Cantonese, gwong dong wah (“Guangdong speech”), is often pronounced gong dong wah, which sounds like “speaking the speech of the east.” These shifts—especially from the “n” to the “l” sound—are widespread, and many Cantonese speakers don’t even notice themselves doing it.