If 2 languages, use number coming first in 820-890 , unless there are different instructions.
eg, use 880 (not 870 ) for Greek and Latin.
If more than two languages are involved from a language family, use the most specific number that will contain all the languages. eg 830 for English, German, and Dutch, since they are all Germanic languages.
Do not use 820-890 for broad groupings such as Indo-European or for unralated literature. For example, use 808 for collections covering English, French, and Russian (all Indo-European languages), 809 for criticism, 800 for a combination of collections and criticism.
If any one language is predominant, class with that language.