J.N.
Does he have a reason to talk????
If you respond to his grunts/pointing/whining, etc. then that is how he will continue to communicate.
Has he had his hearing tested since he was born??? Does he have any allergies??? I would not wait until he's 18 months old.. .Every month at his age is like a year...
Just talking to him won't help - you need to set up situations where he is required to SAY something.. "more" and "help" are the 2 most important words he should be saying...
An Example - at a meal... give him only a small portion of his meal and drink.. when he's eaten what he has.. ask if he wants "more" and then attempt to get him to repeat "more" and if he does.. then give him MORE food/drink.. the more he gets to practice.. the quicker he will get to using more words.
Be in control of his toys/puzzles, etc. set up situations where he has to say something to get what he wants...
When you go shopping.. give him a "shopping list" and let him help you get what's on his list.. ie. diapers, bananas, etc.
Also, sing songs... like Old MacDonald and Twinkle Twinkle Little Star... kids learn more through songs...
and/or have him evaluated an get more suggestions from the Speech-Language Pathologist.
I am a Speech-Language Pathologist with 12 years of experience and I have an 18 month old daughter who has a 100 word vocabulary.