permeate
although you could be talking about a riddle. In that case the answer is -
repeat after me
Repeat after me.
Those letters spell natural.
The letters in "these letters" can spell the phrase "ether settles." The letters can spell shorter words such as trestles, sheerest, shelters, and treeless.
Those letters will spell dollar.
The letters spell 'broccoli'.
Those letters spell delicate.
Those letters spell psycho.
Those letters will spell carnivore.
Those letters will spell artichoke.
The letters can spell the anagram "annotation."
Those letters will spell turnip.
Those letters will spell democratic.