My son is 2 years and 5 months old but not started to talk fluently... says appa Amma,akka n some more words...he follows what we saying but not trying to say it....what can we do further either to consult a doctor or not..?

Every kid takes his own time to reach his developmental milestones, so we should not start worrying comparing our kid to others. Some kids start talking fluently by 2 while others take time and do that only by the age of 4 or so. I think, you should talk slowly to him, so that the words are clearly audible to him and encourage him to repeat words. With practice and time he will catch up. For few more months see how he develops and accordingly decide on whether you need to check with the doctor or not.