the "n" word

Last week Batu did something really strange. We were playing in the living room when he suddenly walked over to the couch, grabbed a pillow, put it on the floor and lay down. Then he looked up at me and said, "Nap." He lay still for a few seconds and said it again. Then again. I assumed he learned this in daycare since the toddlers take a scheduled nap everyday. With this new discovery, I decided to try a little experiment. I usually sit in Batu's room for about 10 minutes after I put him down in his crib at night. Then I go downstairs until he falls asleep, which can take up to 1/2 hour sometimes. Last night, I sat in the chair and waited a few minutes. Then in soft voice, I said, "shh, nap, nap." After five minutes, it was totally quiet. I walked over to the crib and he was asleep. I repeated the "n" word again this evening and he was asleep in 10 minutes. Is his my child or an impostor?