Ming (Agents of Speech) advises parents to teach children delayed gratification to support speech development and learning. He argues that if children always receive immediate rewards they will not learn to work for things, so parents should require a child to ask, do some task, or attempt to talk before granting rewards to reinforce learning and compliance.
Learn to delay their gratification. If they always get it in the get go then they will never work for anything in life. And this is very bad because if your child gets speech delayed and you want them to catch up and the only way is really to always sit them down and teach them something, help them catch up with some homework, then if they don't know what is like a delayed gratification then they will always want to just skip learning. This is something you have to try to do at home. At the very least to help them create this kind of behavior pattern is that whenever they want something they have to ask first, work something, to do something first, talk first, whatever and then they'll get it. Then it will make a lot of sense down the road when you're trying to teach them to catch up. So it needs to be from you. They have to understand that reward comes from the parents and the parents will teach them and as long as they listen and comply they will have rewards.
