Does "–" between methods and documenting have any function in this sentence? What is it trying to say?
Moreover, multi-lingual texts, like vernacular works, have traditionally had strong affinities with realist methods – documenting speech forms as they are spoken – but avant-garde, musical, parodic, sci-fi, psychic-interiorist, artificial/invented, machine, and digital multilingual works have also long followed non- and anti-realist logics.
The words between the pair of dashes are a "parenthesis", a string of words inserted into a sentence while remaining grammatically independent of it.
Such parenthetical statements need to be set off from the sentence and this can be done in several ways: by commas, by brackets (US: 'parentheses'), or by dashes.
In my reading experience, brackets - namely () - are most commonly used. Commas can be problematic as they imply a closer relationship between the phrase and the rest of the sentence than there actually is. Commas are more frequently used with appositional phrases
The parenthesis causes an interruption in the reading (or comprehension) of the sentence so should be neither too long nor too tangential, though very long phrases can sometimes work in a literary context. Essentially it depends on your purpose, and the reading comprehension ability of your target audience.
