FAN C THAT  IV

What do the following words have in common?

CLING
DRIVE
FORT
STATE

HINT:
It has to do with the first letter of each word.

Answer:

If you say the first letter of each word as a separate syllable and alter the spelling, each word turns into a new one:

C-LING - CEILING
D-RIVE - DERIVE
F-ORT - EFFORT
S-TATE - ESTATE