Why English is so hard to learn

"We must polish the Polish furniture.
He could lead if he would get the lead out.
The farmer used to produce produce.
The dump was so full that it had to refuse more refuse.
The soldier decided to desert in the desert.
This was a good time to present the present.
A bass was painted on the head of the bass drum.
When shot at, the dove dover into the bushes.
I did not object to the object.
The insurance was invalid for the invalid.
The bandage was wound around the around.
The was a row among the oarsmen about how to row.
They were too close to the door to close it.
The buck does funny things when the does are present.
They sent a sewer down to stitch the tear in the sewer line.
To help with planting, the farmer taught his sow to sow.
The wind was too strong to wind the sail.
After a number of injections my jaw got number.
Upon seeing the tear in my clothes I shed a tear.
I had to subject the subject to a series of tests.
How can I intimate this to my most intimate friend?"
-The Language of Language: Core Concepts in Linguistic Analysis by Madalena Cruz-Ferreira and Sunita Anne Abraham, P177 on 'homophones' (i.e. words with unrelated meanings, that are spelt differently but pronounced exactly the same).