Every time I am interested in a novel written in English, I struggle to get and read the original version (and I consider myself lucky for being able to do it) and Wuthering Heights was no exception.
On the one hand, we have Emily's outstanding style, which may or may not get lost in translation. On the other hand, the development of the voice and discourse of each character is great (especially taking into account it was written in 1846). I haven't read any Spanish translations so I don't know how translators tackled this problem.
Joseph's speech, which takes the reader to 19 C. Yorkshire, is the only that has been written as it sounds and, because of this, is the most difficult to translate into Spanish, let alone the contrentation it takes to understand it... until you start not reading, but listening to it.
His speech is not written, but oral, and English varieties are almost impossible to keep in a translation: speakers as social individuals have no equivalent in Spanish (or in any other language), there is no social equivalent for Joseph in the Spanish speaking countries.
Maybe Joseph's lines have been written that way so as to make a difference from standard English speakers (a 19 C. English reader would recognise his origin and social class), whose speech is not marked, but they have ended up as a phonological, a sociolinguistics register. The novel immortalised a non-standard English variety.