This paper presents a formal analysis of semi-lexicality, and the early stages of grammaticalisation, i.e. the stages in which a lexical vocabulary item is used semi-lexically. Furthermore, it shows how these early stages impact the morphosyntax of the semi-lexically used item, illustrated with two case studies concerning the Dutch verbal domain. In much of the generative work on grammaticalisation (i.a. Roberts & Roussou (2003), Gelderen (2011)), the main concern is formalising feature loss of vocabulary items. In contrast, my proposal is a step towards formally understanding the stages of grammaticalisation leading up to the adoption of a syntactic feature by a lexical item: the stages in which a semi-lexically used item is still a root. As such, it fills an important gap in our understanding of early grammaticalisation.?