According to Nemours KidsHealth (2019), "All children (yes, even siblings!) develop and refine their language skills at different times throughout their development. So the range of what's "normal" is broad; however, some guidelines can help parents decide if their child might have a language delay.
A typical 2-year-old should:
speak in two-word phrases, like "more juice" and "go bye-bye"
follow two-step commands
name simple objects
have a vocabulary of 50 or more words
be understood at least 50% of the time by a parent
Between 2 and 3 years, vocabulary continues to build and comprehension increases. By 3 years of age, a child should:
speak in three-word sentences
have a vocabulary of 200 words or more (basically, more than you can count)
be understood 75% of the time
understand prepositions (such as, "put it on the table" or "put it under the bed")
use pronouns ("me," "you," "it")
If you feel that your child is not on track, talk to your doctor about your concerns."
Hartnett, J. K. (Ed.). (2019, October). Does my toddler have a language delay? (for parents) - nemours kidshealth. KidsHealth. Retrieved September 29, 2021, from https://kidshealth.org/content/kidshealth/us/en/parents/articles/language-delay.html#catcommunication.