Stages/Milestones
There are five stages to language development: preverbal, before infant speaks; single-word utterances, e.g. dog; two-word utterances, e.g. my truck; refinement, three-words or more, e.g. I hit ball; and complex form, full-sentence, e.g. I like apples and pears (Kretschmer & Kretschmer, 1978).