My two and a half year old has a great vocabulary... but?

she doesn't pronounce the first syllables on a handful of letters. example "S" "P" "H" but like every two weeks it seems like shes talking more and more. Her vocabulary is awesome. she 8-10 word sentences. Her doctor says shes ok, and she didn't qualify to be seen in a speech program ( they said her vocabulary sounded normal for her age). but what are your thoughts? I practice those sounds with her everyday. Do you have a similar baby that does this too? Thanks