'little-documented' is a compound of 'little' and 'documented'. 'little' originates from Old English 'lȳtel' (Old English) where the root meant 'small' or 'of small size'; 'documented' derives from 'document', which originates from Latin 'documentum' (from Latin 'docēre') where 'docēre' meant 'to teach' and the suffix '-mentum' formed a noun.

'little' changed from Old English 'lȳtel' to Middle English 'litel' and eventually to modern English 'little'. 'Document' entered English via Old French (Middle English 'document'), from Latin 'documentum', and 'documented' developed as the past participle/adjectival form meaning 'recorded in a document'. The compound 'little-documented' is a modern English formation combining the adjective 'little' and the past participle 'documented'.

Initially, Latin 'documentum' referred to a 'lesson' or 'example' (something that teaches), but over time it evolved into the sense of a 'written record' or 'official paper'; 'documented' thereby came to mean 'recorded', and 'little-documented' now means 'having few records or little recorded information'.