This contribution reports on a pilot case study conducted on historical corpus data from Old and Middle English (primarily Taylor et al. 2003, Kroch and Taylor 2000) and concerned with the ramifications of an ambiguous adverb (eft, ‘again’) at the syntax-semantics interface. The disappearance of the adverb is linked to the development of again’s partially similar functions during the Middle English period. Akin to studies on the adverb again (e.g. Fabricius-Hansen 2001, Gergel and Beck 2015, Beck and Gergel 2015), at least some instances of eft are claimed to require a particular type of analysis of so-called decompositional adverbs, namely one based on lexical rather than only on structural factors. Furthermore, the development shows characteristics of a cyclical development (cf. Jespersen 1917, van Gelderen 2011)
