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.
As we set out plates, we tell baby that these are circles. We show them picture frames and tell them that these are rectangles. The clock is a circle. The door is a rectangle.
When you play with your baby, describe the shapes of their toys. As you read books, tell your baby these are squares and rectangles. This is an easy way for babies to learn the names of the shapes.
You can get books that show different shapes and point them out to your baby. You can even ask your baby to point to the different shapes. If you use this method of asking your baby to point to different shapes, you will see that your baby can properly identify the differences of the shapes even though they are unable to speak.
Babies are amazing and can learn just about anything. I played these games with my son beginning at birth. When he was around 18 months, we took a trip. He pointed to the ceiling tiles and told me they were squares. He showed me that doors were rectangles and clocks were circles.
All of this was just a game. I never tested him. If he didn't respond when I asked him to find a shape, I simply showed it to him. He never remembers a time when he didn't know how to identify the different shapes.