Over the weekend, Tyler has discovered the letter "b".  It is so cute, he started off on Saturday quietly going "b-b-b-b" under his breath, then by later in the day he was going "ba-ba-ba-bu-ba-bu-bu".  It is so cute to listen to him playing with his new letter.  This is really the first time he's seriously started exploring the consonants.  He's been doing lots of coos and vowel sounds