I agree with Jack Cerf, that JA does not 'do' dialects, and am convinced by you both that it was probably in common usage throughout England at the time. Oh well, Yorkshire is not that romantic (trust me - I spent my teens there), though in fact I had in mind a bit further north. I think we have the Wentworths' social rank fairly well pinned down, but I am still intrigued by the absolute lack of any other background. I favour an Irish connection...