he said "helmet"..with clear speech! go figure!

I am a little surprised today...we were going for a walk with him riding his bike.  I said to Cory to go get your helmet.  I was chatting with a neighbour..she was astonished..and told me that Cory said "helmet" clear as a whistle.  I said "really??"   We have been working on his speech (ling sounds etc..) he is getting some..not all.  Its a new process for him.  Some sounds he is getting is ssss, aaaaaaaa, mmmm, etc.  but can't do "oooo" or "eeee".. this is really puzzling me because I would thought "oooo and eee" would be easier than "ssss or shhhh or mmmm" ?  dont ya think?    and we are trying to get him say few words like "daddy, hello..simple words..nothing yet.. but he could say "helmet"   as far as this goes, he can say "mama, Emma, helmet, bye bye, all gone."      strange......
I wanted to share this with you about helmet..you know how important to wear helmet for biking, roller blading, ice skating etc..well..I did bought one from Walmart and it was so frustrating to keep his CI on without falling off when you put on the helmet?  it has to be a tight fit for proper use of helmet right?   so the cheap Walmart doesn't work very well.  However, I just happened to stumbled on second hand helmet at garage sale and I just thought it was cool looking and saw how the strap works. Im thinking mmmm, that straps would work!  voila..it really does!  you can just put the helmet on THEN tightened it to keep the CI in place!   and we have no problem with him wearing helmet and CI not falling off!!!!  I did some checking..the helmet is expensive, you can get them from a bike store..the retail price are about approx. $40 to $50.   Giro is a good helmet.   But its worth it!  I know that his head is protected, and he is using it and is able to hear the environmental sounds around him while wearing it.  Isn't it worth it??   The bonus part is the helmet lasts about 3 to 5 years..so..see it for yourself.   adjustable to grow into it??