Taking a college linguistics course, the professor claimed that the spelling of words was not accessible to the part of the brain that decided how to pronounce them. This seemed unlikely to me, so I decided to start distinguishing words starting with 'wh' from ones starting with 'w'. For example, "whale" vs "wail" or "while vs "wile". This is a distinction English traditionally made, but is no longer common.

When I first started doing this I would screw up sometimes or pause very slightly before saying a word starting with 'w' or 'wh'. Over time consulting my sense of spelling has gotten completely automatic, however, and ten years later I just don't notice anymore.

(The alternate explanation would be that in this time I've just learned new pronunciations for all the common w/wh words, and haven't actually made any connection between spelling and pronunciation. The way to test this would be for someone to put me in a situation to elicit uncommon words like "wintle," "weevil," or "whizgig" without letting me know what was happening, letting me see them written, or giving me time to think.)