Here are some GENERAL talking rules:
- 1 word by age 1
- two-word phrase by age 2 (things like 'thank you' are considered one idea and so it's not a two-word phrase. A two-word phrase would be two different ideas being linked... "mommy shoe", "up please", "go car", etc)
- 10-20 words by 18 months
- about 100 words by age 2
- vocabulary of 1000 words by age 3
- Sentence length of 4-5 words by age 4
- Uses proper future, present, and past tense of words by age 5
- Should pronounce every sound correctly by age 6
Familiar listeners (close neighbors/friends, parents, siblings, etc) will typically understand more of what a child says. However, by age 2 1/2 - 3, an UNFAMILIAR listener (stranger) should also be able to understand 80-90% of your child's speech.