Lazy pronunciations (or lazy sounds) are the “left-over” phonetic traits from childhood for some native-speakers. Some sounds are difficult to pronounce for a child and they are replaced by similar sounds which would take less effort to pronounce.

As the child grows older and the linguistic ability has developed better, the lazy-sounds will be replaced by the correct sounds. The correction sometimes happens naturally and sometimes requires guidance from the adults.
Unfortunately, this process might not happen to some people, for many different reasons. This is why when people speak with lazy sounds, they sound like a child.

1. ‘n’ initial replaced by ‘l’.
   E.g., 男 (man) – naam4 becomes laam4 / 你 (you) – nei5 become lei5
2. ‘ng’ initial disappears.
   E.g. 我 (I) – ngo5 becomes o5
3. ‘ng’ final replaced by ‘m’.
   E.g. 五 (five) – ng5 becomes m5

In recent years, many young pop-stars suffer seriously from lazy pronunciations and this seems alright, if not trendy. As a result, many youngsters follow them. This was certainly not the case in the past, when lazy pronunciations were less tolerated. I still remember when I was a kid, a children TV program was launched for only a week or so, and one of the hosts got replaced. The reason? Many parents complained that she spoke with lazy sounds.