I don't doubt that dogs are smarter than cats, but dogs are far more social and are motivated to learn by that social connection. Cats can also be trained, but it's a lot more work to keep them motivated.

Cats do communicate a lot, but it's physical and sometimes subtle; eye contact, body rubbing, head butting, contextual waiting, and so on. Our cats very rarely meow unless they haven't been noticed, or, with the Norwegian, when she wants attention and she has a toy in her mouth she wants to play with - she loves playing fetch with toy mice.