My 8 mnths old will not talk?

my son was about 2 months early...but he started holdin his own bottle at three months and sitting up at five and crawling at five and he kinda walks now at 8...he was tryin to say momma...and sayin bababa (bottle)...but now all he does is make funny sounds i talk to him all the time..his daddy thought it was funny to make him yell but thats all he does now...should i b worried