Is it normal to not always understand what my 2 year old is saying?

Is it normal to not always understand what my 2 year old is saying?

Scott Cohen (Pediatrician, Cedars-Sinai Medical Center) gives expert video advice on: Is it normal to not always understand what my 2 year old is saying?; What are the developmental milestones for children 3 to 5 years olds? and more...

Words may not be articulated well, a syllable may be dropped off, but this is very normal. Yet, again I want to see understanding and word explosion.