So you know how in American English, the word vase is often pronounced /vɑz/ when describing an expensive or elegant item, and /vejs/ when talking about something more everyday and cheapo?
Well when I was a child I did the same thing with sew, using the spelling pronunciation /su/ — which I perceived as fancier or more old-fashioned — when talking about expensive or elegant needlework or whatever, and the conventional pronunciation /sow/, which I frequently spelled sow, when talking about more everyday needlework. So I might've said a hand-{sewn|/sun/} dress for the fairy tale princess but a {sown|/sown/}-on button on my second-hand jeans — though keep in mind that these weren't necessarily strict and absolute distinctions, just overall tendencies.
My running theory for how I ended up inventing this distinction "out of thin air" is that I had conflated the words to sew and to sow: a seed drill and sewing machine after all both move over a flat surface to make holes in it at regular intervals, into which they quickly insert something, so people kinda do sow fields with seed in the same way as they sow shirts with thread. And then because I already believed these to be the same word, then seeing the same word with both a spelling that makes sense and a spelling that doesn't, caused me to rationalize the irregular spelling as representing some sort of archaic variant pronunciation — which I could then use when I wanted to sound fancy.
And yeah, once you make that sort of rationalization, then confirmation bias can take you a long way. But with time I did end up getting corrected and eventually I just stopped making the distinction.
Which is maybe a bit of a shame, because it would've been pretty cool to make that kind of distinction.