Question

Can you help me to fill in the blank to
this sentence?

Molly is an older 4-year-old and
her teacher is concerned about her _________ speech development because she is difficult to understand and this has not changed in the last year.

1. receptive
2. expressive
3. rate of speech
4. nasal

Would "expressive" be the most appropriate word to use?

Yes. Expressive is the best word.