For 9 Months old and on.
Start adding to your description of objects and increase the number of words strung together towards a complete sentence as time goes on. For example, emphasize: red toy, green spinach, or fast truck. Example of expanding your description: that bug; that little bug; that little red bug; that little red but is crawling away. This isn’t to be done in one sitting, but over the course of your time spent speaking to him.
WHY? William Fowler, an educational psychologist, developed a program that emphasizes how and when to speak to babies. The essence of his program is to introduce language development stages before the baby has exhibited meeting each stage. He studied the program’s effectiveness on 30 children and found: first words spoken between 7-9 months; some spoke sentences at 10 months; and most became proficient in basic rules of grammar by the age of 2 years old. These basic language milestones were achieved several months ahead, and in the case of grammar, achieved it a whooping 2 years ahead when compared to babies in normal environments.