Babies are learning from the moment of birth. You don’t need to wait until your baby is a certain age to begin teaching your baby to identify shapes. You can naturally teach them to recognize shapes by using this method.
Language is so important for baby’s brain development. The more language the baby hears; the better. Baby will learn language faster and more efficiently. Studies have shown that the amount of language a baby hears from birth to two years old will determine their future academic success. This means that as parents and caregivers, we need to speak to our babies often, about everything.
Since this is how babies easily learn, we can teach them all kinds of things before their second birthday, including properly identifying shapes. We just need to point out the types of shapes we encounter in our daily life. As we see objects, we just tell our baby the shapes.
http://ezinearticles.com/?How-to-Teach-Your-Baby-Shapes&id=2304184
http://www.babyclassroom.com/shapes.html