Multilingualism in medical texts

Multilingualism is not a purely literary or even everyday phenomenon. Other types of writing also tend to be multilingual. For example, during the medieval period in the UK, medical writings used more than one language in a single text. Write Irma Taavitsainen and Päivi Pahta in their Medical and Scientific Writing in Late Medieval English (2003):

"Multilingualism has an important role in scientific and medical writings produced in medieval England. The tendency to combine materials in different languages appears to be more prominent in medicine than in other disciplines, although language mixing is also attested, for example, in astronomical-astrological and alchemical writings of the period. The proportions of languages and patterns of switching in mixed-language materials vary. Primarily Latin materials contain parts in English or French, French materials include Latin and/or English passages, and English materials incorporate Latin and/or French."

It might be a truism that, in a society where the learned language is not the market language, writers (and other users of language) will tend to use more than one language in a single text, written or oral. Either the learned language or the market language will prove to be insufficient for one's communicative needs, especially since the languages involve different cultures or subcultures, not just dictionaries.