Learning readiness refers to the process by which children under the age of 6 prepare for direct instruction in reading and math. Prior to the age of 6, it is developmentally inappropriate for most children to receive any kind of direct instruction in reading or math. Instead, children should be exposed to rich vocabulary (through songs and stories) and build social skills as well as fine and gross motor abilities.
According to child development specialists, “Learning progress may actually be slowed by overly academic preschool experiences that introduce formalized learning experiences too early for a child’s developmental status.” —Rebecca Marcon, Developmental Psychologist
Furthermore, "Early learning programs that are appropriate for a child’s developmental level provide opportunities to learn through play and hands-on exploration. Through this type of learning, children test new knowledge in a relaxed setting and then naturally relate it to existing knowledge and store the new information." - Brain development article (see link below)
Here is a great article on the Brain Research behind the developmental approach: http://larrycuban.files.wordpress.com/2013/04/brain_dev_and_early_learning.pdf
If you want to help your pre-school-aged child prepare for Kindergarten, please seek help from someone who understands child development (and one should NOT assume that ALL elementary school teachers do because even though I was required to take child development courses at the University of Maryland, many Elementary degree programs across the country NO LONGER REQUIRE undergraduates to take them).