None (77 words)
baby, ball, bear, bed, bell, bird, boat, box, boy, bread, brother, cake, cat, chair, chicken, children, coat, corn, cow, day, dog, doll, door, duck, egg, eye, farmer, father, feet, fire, flower, game, garden, girl, good-bye, grass, hand, head, hill, home, horse, house, kitty, leg, letter, men, milk, money, morning, mother, name, nest, night, party, picture, pig, rabbit, rain, ring, robin, Santa Claus, school, sister, song, squirrel, stick, street, sun, table, thing, time, top, toy, water, way, window, wood
Once (18 words)
apple, back, birthday, car, Christmas, farm, fish, floor, ground, man, paper, seed, sheep, shoe, snow, tree, watch, wind