What do the following words have in common, other than beginning with CH?

CHEAT
CHIN
CHEEK
CHEAP
CHILL
CHIEF

HINT:
It has to do with the first letter and the  sound of the words.

Answer:

The first letter of each word can be changed to S to phonetically create new words. The new words will have an altered spelling:

CHEAT - SHEET
CHIN - SHIN
CHEEK - CHIC
CHEAP - SHEEP
CHILL - SHILL
CHIEF - SHEAF 

Credit: Will Shortz in The Puzzzlemaster Presents
CHEAT SHEET