Ming from Agents of Speech recommends waiting until age two for a speech assessment, when kids can use two-word phrases and sit through testing. Before that, short attention spans make it hard to get useful results. Assessments check sound production, vocabulary, and whether they understand simple questions.
The best time to get a speech and language assessment is after two years old. A child that is around one year old. Plus their attention span is very short and they don't really have the muscles to sit on a chair for that long and interact with you an extended period of time. There are other things to look at, but as a speech and language therapist, what we look at is communication. How many sounds they can say correctly, what kind of words and phrases do they have? If they really have language delay or disorder, there's not much to be assessed. One of the biggest reasons is because there's not enough things to demonstrate to the parent. Younger a child is the less structure you can give a child to do therapy because they would like to run around, they would like to take breaks, they would like to crawl and roll over and so on. So I think really after two is a lot better. By two, children should be speaking in two word phrases. How about comprehension? Comprehension is very easy. You can look at question if your child cannot answer at 2 years old, like yes or no questions, what is this? What is that? Also like choice questions, go for assessment and have it comprehensively looked at by a therapist.
