Letters and numbers, along with animal sounds, vehicle sounds, signs, and homonyms (such as "da" for dad and dog, or "ba" for bath and ball), all contribute to the word count.
As it stands, the milestone for three-year-olds is set at 250 words. However, on average, three-year-olds can utter approximately 1000 words. Any number falling within this range is deemed to be within the realm of "normal."