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 this new sound.  He's been doing lots of coos and vowel sounds,  but this is really the first time he's seriously started exploring a consonant.