By the time toddlers can say twenty-five words, they can understand about 170. At that point, their spoken vocabulary is apt to consist of a few names of family members, foods, body parts, and animals; a smattering of actions like [pick me]up and open; some adjectives like soft, and pretty; the adverbs where and there.
When beginning speakers point at an object while saying its name, they usually mean “I want it.” After youngsters are able to say about fifty words, somewhere between sixteen and twenty-two months, they realize that everything has a name. Then the pointing changes from a demand to a question. They don't want the item; they want to know what it is called. Suddenly their vocabulary explodes as they flit from object to object, asking to know the name of everything they see. Parents' responsiveness pays off in a big way. Toddlers going through this stage can master several new words each day.