The Functions of Auxiliary Do in Middle English Poetry: A Quantitative Study

The higher frequency of auxiliary do in poetry than in prose in Middle English (1150-1500) is one of the puzzles of the history of this construction. Previous studies have argued that the role of auxiliary do in poems was to place the infinitive at the end of the verse to make rhyme easier. The aim of this article is to examine to what extent auxiliary do was used for rhyme purposes and, furthermore, to determine whether it had other functions. On the basis of a conditional inference tree and random forests, this paper shows that auxiliary do was indeed used as a metrical tool to place the infinitive at the end of the verse to facilitate rhyme, although the degree to which poets used auxiliary do varied from dialect to dialect. The statistical analysis reveals that the auxiliary construction served also other functions, particularly in the Eastern Midlands and Northern dialects, where do favored the integration of verbs of foreign origin and ensured the metricality of the verse by maintaining a regular distribution of the beats in the line.