To anyone who is saying Growlithe should know Growl, please
read.
The people who design Pokemon games read in Japanese. In Japanese,
Growlithe's name is ガーディ (pronounced like "gadi"), and growl's name
is なきごえ (pronounced like "nakigoe"), so the game designers saw no
reason for Growlithe to learn growl.
“Twenty years from now you
will be more disappointed by the things that you didn't do than by
the ones you did do. So throw off the bowlines. Sail away from the
safe harbor. Catch the trade winds in your sails. Explore. Dream.
Discover.”
-H. Jackson Brown Jr.