Hi J....
Congratulations on your new little one! Your questions are totally natural, and your baby sounds perfectly healthy! It's interesting to note that often the first sounds that babies make are dada, mama, baba, because the muscles they use to make those sounds are the ones that develop well from sucking. Babies often make strides in one area of development, and then it seems like they stall, but it's only because their brains are busy working on a different area.
It also sounds like he found a fun way to explore how his body works and the world around him by waving his arms up and down - he's learning about movement, gravity, and exercising his muscles. It probably won't be the only quirky looking thing he'll do... but it's just how they figure things out and develop physically, cognitively, and emotionally.
Going through all of these changes with a baby can be exciting and overwhelming. I am wondering if you've considered taking a mommy and me class. It's a wonderful way to meet other moms, get all of your questions answered and learn a ton about your baby's development and your parenting approach. I'm offering one that starts next week in Beverly Hills, Brentwood, and Studio City. If you are interested, please check out my website at www.inspiredmotherhood.com
Also know that I'm available as a resource if you ever have any other questions!
Take care and enjoy your precious little one!
D.