Activities focused on hearing similarities and differences between the sounds that make up words helps children develop an understanding of sounds letters make. Encourage your child to mimic the sounds as you sing.
Fill a paper bag or a ziploc bag with some magnetic or foam letters and cut a hole to make a mouth in the middle. Add googly eyes, pom poms and some other decorations to make it look like a monster.
Play feed the monster by laying out a few letters in front of the monster and asking your child to feed the monster a specific letter. For babies, choose any of the letters and throw them in the monster's mouth and say the letter out loud as the monster 'eats' them.