I know it's common for toddlers to have colds but DS (2.5) has had permanent snotty nose/cough since he was 6 months old and frequent ear infections. He has an inhaler for when he's very wheezy and sometimes a course of antibiotics when the infections are bad. His speech is behind that of many children his age I have observed when out and about and he often doesn't hear when you call his name, but his hearing is good enough that if I start to sing quietly to myself when pushing the buggy he will tell me not to sing! 
so I think he can hear sound fine but the detail may be foggy? Which could be responsible for how poorly he pronounces words. He attends nursery 4 days a week and they (independently) mentioned their concerns with his speech a few months ago, so we went to a SALT drop-in but she said just to monitor him for time being, and if no improvement by age 3 then to come back. 
I have mentioned to GP my worries that his colds/ear infections could mean he is living in a permanent fog. She agreed his ears did always seem to be inflamed but she didn't think it was necessarily impacting on his speech. I know you get grommets for glue ear but apparently this isn't what he has. I'm a bit stuck/confused/worried and don't want him to get any older with this speech delay. Has anyone experienced similar? Perhaps my best course of action is to bite bullet and go to private SALT? Or back to GP for grommet referral? Thanks for any advice.