They say it falls mainly on the plain. Eliza Doolittle, in My Fair Lady, practices her vowel sounds endlessly. It seems she will never replace the "ow" with the "long a" sound. Henry Higgins ruthlessly drills her.
Writing teachers deal with similar issues. Today I drilled "they're", not "their"; "it's", not "its"; "too", not "to". And of course all the reverse combinations of troublesome homonyms. Accept and except are two word pairings that are continually confused. One could go on and on with all the regular words blunders.
I once had a student defiantly tell me in front of the whole class that there was no difference between "to" and "too". I respectfully told her she was welcome to her opinion about things that had some room for variations, but this was not one of those cases, and she was just plain wrong. Her defiance continued unabated, and so did her mediocre writing.
Become intelligently literate is as difficult as being able to perfectly enunciate language. So for now, I will continue with "here", not "hear" and "where", not "were", while the rain in Spain continues to fall mainly on the plain.