Simplify the following text for a Grade 8 native English-speaking person.
Original: It is from this trait that they got their name , which comes from Anglo-Norman dormeus , which means `` sleepy ( one ) '' ; the word was later altered by folk etymology to resemble the word `` mouse '' .
Simplified: The Anglo-Norman word dormeus means `` sleepy ( one ) '' ; the word was later changed to resemble the word `` mouse '' .