Not as fluent in English as I thought

Ask me where I'm from and I'll say Yorkshire. I use a smattering of dialect, but not nearly as much as I used to, and unless you know me well you're unlikely to hear the strongest version of my accent. I write in English, as you can see, and being a native speaker I thought I was pretty fluent. Until I started doing a deep edit of a couple of short stories during an online course.

The exercise was about getting specific. Cut the adverbs and use the most fitting verb. Ditch the abstract notions and make them concrete. Here's what I wrote as my experience of working through the story I'm focusing on the most, which is set in the 1980s on a farm in the Yorkshire Dales:

I had (I think) almost nothing properly abstract and only one adverb (breathing heavily). I wondered how much is to do with this story being in a working class Yorkshire setting so I feel free to use more evocative and precise phrases like he clattered down the stairs, he brayed on the wall, the radio wittered. I'm going to investigate another story where I've used a more middle-class voice and see if I've used 'standard English' i.e. a smaller vocabulary and hence relied on adverbs more.

And you know what? I had.

As I suspected, the middle-class voice story I was thinking of has: talking quietly and earnestly, walked more slowly, ran quickly away, held tightly [several times!], coughed loudly. Not to mention a couple of 'very' and some abstract notions like feeling better, being kind or afraid. Wow.

Now, either I was having a bad day when I wrote the 'middle-class' story (and every subsequent time I've gone through it) or I have some kind of block when I'm writing in a posh voice.

I've talked about code-switching before (not least when I wrote about accent at No Writer Left Behind) but I always thought I was pretty good at it. My vowels sound northern (u and a are dead giveaways) but I didn't think translating the odd word (something/anything/nothing instead of summat/owt/nowt, for instance) was seriously stifling my creativity. But all that is in spoken English, and thankfully I don't get to go back through conversations at work to see how large a vocabulary I've used.

Written down, it's there to go over later. Written down, it also has to follow rules about what gets written in books, 'proper English'. Do I self-censor because I think words like clattered or brayed aren't allowed in written English (slang? impolite? common?), or because I think they're not universally understood (dialect? old-fashioned?), or because I think they're not used by the kind of person with the voice I'm trying to write in?

It's an interesting situation, it's shown up my assumed fluency in switching and made me stop and think. Maybe what it comes down to is if I'm consciously writing 'northern-normal' - what to me is the default - then as long as I can imagine me or my Nana saying it, it's fine, but for the middle-class, the BBC accent, I have to be able to imagine someone reading it from a book on Radio 4, and that imposes a whole mass of constraints which I'm clearly not comfortable with navigating.

I think my conclusion is that I should take my own repeated advice and write more in shades of my own voice.