DD i would possibly just monitor if he is ok with other noises and if you feel he is than i wouldn't worry. DS2 he's nearly 2.5yrs old and has only really just started saying things in the last couple of months, he was always behind what the CHN wanted so i just stopped taking because he was infront with everything else but that never seemed to matter. I was worried for a time there but now he sits with DS1 and says words and spells them too with help of course, some kids are just slower at talking.