I’m steeped in amusement today
By a goof that keeps coming my way.
At least twice I have seen it
So it’s time that we clean it
From the phrases that some of us say.
Consider the little word curb;
It’s used as a noun and a verb.
Appetite or enthusiasm
Or or a bad muscle spasm,
It means to control or disturb.
A curb is a physical restraint;
With that use I have no complaint.
Curbside pickup or check-in,
Correct uses without reckon
But “a steep learning curb” it ain’t!
Note: Learning curb is a good example of an “eggcorn.” Have you more to throw into the basket?
Word Nymph 
An eggcorn I keep seeing in writing is “baited breath”.
(mentioned here: http://kitchenmudge.wordpress.com/2011/08/17/hes-doing-that-again/)
I had not heard “learning curb” before. I think I suffer from that, though. Many curbs get in the way of my learning anything new. 🙂 Love your poem!