A nice article by Rebecca Gowers in The Guardian 26.03.2016
(The printed edition gives a little more context: Rebecca Gowers is the great-grandaughter of the original “style guide”, “The Complete Plain Words”. The article is a nicely worded dig at language pedants. David Crystal would approve I think).
True, this is about English, but perhaps a similar article might be written about pedantry in Welsh as well. 
Except that Welsh pedants are on far shakier ground, what with there being no real accepted ‘standard’ Welsh. I love the fact that I can come out with some awfully strangulated stuff in Welsh while under pressure, and people mostly (with the main exception of people who have also learned as adults) shrug their shoulders and assume that “that’s just the way they say it where he comes from”. 
That’s excellent!
I love the You tube clip with the adorable Miriam Margoyles.
I remember watching that episode of Graham Norton (having been tipped off by a friend that it was a good one) and crying laughing - the combination of Will.I.Am and Miriam Margoyles is totally bonkers, but just pure alchemy.
Back on topic, I work in a field where I am subject to the rantings of a lot of pedants, and it does get tiresome after a while. So I’m particularly touchy about it in Welsh as well.