7 month old doesn’t babble

My baby will be 7 months old on Wednesday, and he’s never babbled/made any consonant sounds. He occasionally coos, but mostly he just squeals/grunts/squeaks like some sort of baby dinosaur. He’s meeting all of his other milestones, and he readily laughs, smiles, and socializes. The pediatrician wants to refer me to speech therapy in one month if he doesn’t start babbling - is it normal for him not to be babbling yet? And does anyone have any experience with speech therapy - not sure what they do at speech therapy when a baby is so young?