14 month old son's development?

I'd give it a bit more time - if you're in to your doctor at 15 months and he still hasn't said his first word at all then bring it up and ask for an assessment. It could be nothing, or it could be some sort of delay. Our doctor was a bit concerned at our 12 month checkup and referred us at the 15 month checkup when our daughter hadn't said her first word. With language development it is best to intervene earlier rather than later so I wouldn't let it go too much longer before you get assessed, just to be on the safe side.