| Word category | MBCDI class (number of items) | Examples |
|---|---|---|
| Common nouns | Animal names (36) | animal, cow, kitty, sheep |
| Vehicles (9) | airplane, car, motorcycle | |
| Toys (8) | ball, book, toy | |
| Food and drink (30) | apple, milk, water | |
| Clothing (19) | hat, pants, shoe | |
| Body parts (20) | ear, hair, tummy | |
| Furniture and rooms (24) | door, potty, TV | |
| Small household items (36) | box, cup, watch | |
| Outside things and places to go (27) | home, snow, zoo | |
| Predicate words | Action words (55) | eat, go, love |
| Descriptive words (37) | all gone, bad, dirty | |
| Social words | Sound effects and animal sounds (12) | meow, woofwoof, yum yum |
| People (20) | babysitter's name, mommy, person | |
| Games and routines (19) | night night, peekaboo, thank you | |
| Closed-class words | Words about time (8) | day, now, today |
| Pronouns (11) | I, it, you | |
| Question words (6) | how, what, who | |
| Prepositions and locations (11) | back, down, up | |
| Quantifiers (8) | all, more, not |
Note. MacArthur–Bates Communicative Development Inventories (Fenson et al., 2006).