Single Words: The second stage is known as the one-word or holophase stage of language development. Around the age of 10 to 13 months, children will begin to produce their first real words. While children are only capable of producing a few, single words at this point, it is important to realize that they are able to understand considerably more. Infants begin to comprehend language about twice as fast as they are able to produce it.
Two Words: The third stage begins around the age of 18 months, when children begin to use two word sentences. These sentences usually consist of just nouns and verbs, such as "Where daddy?" and "Puppy big!"
Multi-word Sentences: Around the age of two, children begin to produce short, multi-word sentences that have a subject and predicate. For example, a child might say "Mommy is nice" or "Want more candy."
As children age, they continue to learn more new words every day. By the time they enter school around the age of five, children typically have a vocabulary of 10,000 words or more.