Auchinleck has held a prominent place in discussions of the history and development of Middle English. Its texts provide important information about English dialects at an early stage (the 1330s) and dialect profiles are included in the Linguistic Atlas of Late Medieval English for all five Auchinleck scribes who copy literary texts (it is not possible to analyse the dialect of Scribe 4 as he copied only the Battle Abbey Roll, a list of names). These profiles locate the written language of Scribe 1 in Middlesex, Scribe 3 in London, Scribe 5 in Essex and Scribes 2 and 6 in areas close together on the Gloucestershire / Worcestershire border. Scribes 1 and 3 have received particular attention as they form a basis for M. L. Samuels' (1963) well known typology of late medieval London English, where he describes their language as representative of a distinctive stage (his 'Type II') in the development of the London dialect. The collection of texts in Auchinleck have also been important to studies of phraseology and style, such as the recent analysis of pious language in romance by Dalrymple (2000).

Auchinleck contains a large collection of Middle English poetry from a period when relatively few ME texts survive. That is, it offers a rare snapshot of the kind of English literary texts which were in circulation in England in the period before Chaucer. A wide range of genres are represented in the manuscript which includes romance, hagiography, texts offering basic doctrinal instruction, a chronicle, humorous tales, and poems of satire and complaint. That couplet and stanzaic verse forms dominate is indicative of the manuscript's Southern and Eastern axis. However, Auchinleck also includes two alliterative items (Þe Simonie and The Four Foes of Mankind), as well as two more items in which alliteration is a marked feature of style (Sir Tristrem and The Thrush and the Nightingale) and these texts of Northern and Western origin indicate that the London compiler of Auchinleck and London readers at this date had access to texts from far beyond their own immediate geographical region.