My son saw a speech therapist at 2 for not talking enough (probably due to chronic ear infections). He was still just using 1 syllable words and no sentences at all. We had a great speech therapist. She did spend a lot of time on pictures and sign language, but she verbalized while doing it. As I understood it, she first wanted to ensure he understood the basics of communication - how to ask what he wanted. Sign language is much easier than talking at that age. He picked up the signs for want and please very quickly. Then, she worked on words and gave him a template for basic sentences.
My son only worked with her for 6 months, but it was enough. It was amazing how quickly he picked up new words and phrases once she unlocked it for him.
Another thing to consider - there are free programs in some states. It's called "Help Me Grow" in my state or "Early Intervention". It's for toddlers and preschoolers with developmental delays. My son, at 2, qualified for the program because he was 3 months behind in speech. Those ladies were wonderful! They came to our house or daycare to work with my son, and they had "groups" for him to learn with other kids.
He's 4 now, and he's firmly in the "normal" category for speech.
Your pediatrician should know all about the programs in your state. But, I'm really surprised your pediatrician waited this long to intervene. Perhaps you should consider another pediatrician?
Good luck!