The speech language therapist in me can't resist adding to this ....
My first piece of advice is that if you are concerned, you are best to get an assessment with a speech language therapist and they can give you the right advice about whether he's absolutely fine and will work it out, or if you maybe need to do something. At that age, it may be giving you advice about activities you can do to promote his speech and language development. Details of SLTs in NZ can be found at
NZSTA
Here are a couple of links to information sites from international SLT organisations that can give you more info as well. The ASHA ones give you tips about activities you can do ...
ASHA - Late blooming or language delay?
ASHA - Language development from 1-2
ASHA - Language development from 2-3
CASLPA - Normal language development and when to get advice
The CASLPA (Canadian SLT organisation) guidelines say:
How many words should my toddler be using?
On average, a child should use at least 200 words by the age of two. By the age of four her vocabulary should be at least 2000 words. As general benchmarks, consider whether your child can:
• Say her first word by her first birthday
• Combine two words, for example “Mommy up” by age two
• Use three-word phrases and short sentences by age three, like “Puppy come here”
• Use four or more word sentences by age four, as in “I like to play dolls”
When should I visit or speak to a speech-language pathologist?
Seek answers if your child:
• Shows no reaction to sound in the first three months of life
• Is not babbling and making sounds by 10 months
• Doesn’t gesture, show, give or point to get something by 12 months
• Doesn’t understand simple commands like “See your ball? Get your ball!” by 18 months
• Doesn’t pretend play, like feeding a stuffed toy, by 18 months
• Is not using single words by 21 months
• Doesn’t understand a variety of simple concepts like “big-little, up-down” by 24 or 36 months
• Is not joining two or three words by 27 months
• Ls extremely difficult to understand at age three - the listener has to guess extensively about what the child is saying
• Doesn’t understand or is unable to reason questions like “What do you do when you're hungry/cold” by the age of three or four
• Continues to make numerous grammatical errors at age five so that the communication burden falls to the adult to figure out what’s been said
• Shows other communication problems, or you have a sense that something is just not quite right with the child’s way of communicating or interacting
Hope this is of some help. Like everyone has said, some babies are late talkers (I didn't talk till 3), but I thought some info from the different SLT organisations might be helpful as well.