Diff btwn language and development delay

My boy is facing language delay(both receptive and expressive), speaks only 4 to 5 words like mum, emee, thik, hmm, haan and occasionally papa or mummy...as receptive language is also not developed yet, so he can't understand what we are saying, he understands only few things. That's why he doesn't know body parts names , colour names and other basic things like this and doesn't follow most of the commands either. We are taking speech therapies for him and they are asking us to take special education too!! My question is, which should come first, receptive language or basic things and developmental basics? If his receptive language isn't developed yet, so how would he understand things like colours.or body parts ?? Plz guide me best according to our situation 🙏🏻