All children learn to talk in the same order. First they use single words, then phrases and finally whole sentences. But apart from this, it’s very individual how children learn and master speech. They each have their own personal timeline. It may be fast or it may be slow. Sometimes nothing seems to happen at all, then suddenly there's a giant leap forwards. So don’t make comparisons. This is a good rule to remember for lots of things.
It’s natural to worry if your child seems to be talking much less than their peers (sure, you know you shouldn't make comparisons – but it's hard not to!). Perhaps your toddler uses fewer words, or uses lots of words but no sentences. If your child understands your questions, is able to follow very simple instructions and clearly understands what you’re saying – relax. Their speech will get there. Just give it time. By way of comfort, remember that late talkers are quicker to develop fairly mature language. This means they soon catch up. If you’re still worried, speak to your GP or nurse. And you can read more about encouraging language here.