Gaga. Mama. Baba. Listening to a baby talk at this age is a bit like searching for diamonds in a rock pile. Real words will be surrounded by nonsense syllables. And even when you hear a word, it's hard to tell if he really means it. He may say "no" when he's thinking "yes," and he may say "mama" for absolutely no reason at all. He's still figuring out what his mouth can do. You should keep encouraging him to talk, but don't hold him to his word.
He may not be articulate, but his brain is buzzing. For one thing, he pays close attention to the people around him. He listens to other people's conversations, and he likes to imitate sounds and actions. He'll be excited to play a crawling game of follow-the-leader or any other copycat game, especially if he gets to take the lead every once in awhile. He still has a tiny attention span, though, and he'll quickly tire of any activity if you do it over and over again.
If he needs a break from follow the leader, you can always try another classic: Hide and seek. He'll love finding a toy hiding in a basket or a person crouching behind a chair. You're not dealing with a super sleuth, though, so make sure he watches you choose a hiding place. If you're doing the hiding, try leaving an arm or leg in plain view. He doesn't really want a challenge. He just wants to have fun.
When he plays with his toys, he'll probably favor things with spinning wheels, flapping doors, or other moving parts. He likes to keep things in motion. If you build a tower of blocks, he'll knock it down as fast as he can.
He certainly doesn't need a pile of elaborate, expensive toys to stay busy or entertained. At his age, an empty oatmeal carton or a set of plastic measuring cups will give him all the fun he can stand. He loves to fill, shake, and empty all sorts of containers. He may be making a lot of noise or at least a good mess, but he's also learning about sizes and shapes. Some toys will fit in an oatmeal carton, and some won't. Its another breakthrough for baby science.
He's becoming an avid experimenter, and you happen to be his favorite guinea pig. He wants to find out how you'll react in different situations. What will you do when he yells at the top of his lungs? What are your feelings about pudding in the vents? And how committed are you to the "don't pull the cat's tail" rule? He's testing his limits and your patience at the same time.
When he tries one of his little experiments, you'll have to help him understand the results. Instead of saying "no" all the time, try giving him simple, to-the-point explanations: too loud, too messy, be nice. Even if he immediately goes back to causing trouble, try to stay patient. Keep your expectations low, and don't get frustrated if you feel he's testing you too much -- if you are patient and consistent, he will eventually get the message. Noise, messes, and nervous pets are just a part of life when you have an active baby in the house.
In between the missteps, there will be plenty of times when he acts like the perfect baby. Be sure to give him lots of attention when he's playing nicely or petting the cat gently. He'll learn that doing the right thing is easy and rewarding. It's a discovery that will definitely improve his life, not to mention yours.
Sears, William and Martha. The Baby Book: Everything You Need to Know About Your Baby From Birth to Age Two. 2003. Little, Brown and Company.
American Academy of Pediatrics. Caring for Your Baby and Young Child: Birth to Age Five. 1998. Bantam Books.
University of Wisconsin Extension. Parenting the first year: month 9-10. 2005. http://racine.uwex.edu/flp/documents/PFY9-10.pdf
University of Georgia Cooperative Extension Service. Baby Bouncer. Tenth month: budding independence. September 2000. http://www.fcs.uga.edu/pubs/PDF/CHFD-E-39-10.pdf