Upvote:4
The superstitions are probably quite old, because they originate in the spoken language.
The Chinese word for four, written "si" in Roman characters, is a h*m*nym with the word for "death" and therefore unlucky.
(My father (an immigrant from China) once warned me not to read a book behind someone playing a game unless I wanted him to lose because the Chinese word for book, written "shu" is a h*m*nym for "lose.")
Edit:
I was reminded by Kenny LJ that the Chinese word for eight, written "ba," is a h*m*nym of a word for prosperity or "development." Slightly mispronounced, it is part of the Cantonese New Year's greeting, "gong hei faat choi," which literally translates to "good wishes for developing wealth."