At what age should a child be able to use thousands of words and form 3-word phrases?

At 3 years of age, children typically reach a significant milestone in language development, where they can use thousands of words and begin forming 3-word phrases. This stage reflects a rapid expansion in vocabulary and the ability to put together words in simple yet meaningful sentences.

By the age of 2, children are usually beginning to combine words and may use simple phrases, but their vocabulary is still limited compared to the capabilities seen at age 3. By the time they reach 4, children often exhibit more complex sentence structures and a significantly larger vocabulary, which goes beyond the foundational skills established by age 3. At 5 years, children's language continues to develop further in sophistication and complexity.

Therefore, the age of 3 is the appropriate benchmark for expecting a child to be using an expanded vocabulary and the ability to construct 3-word phrases effectively.