When languages that are known to be in contact share features, it is often a simple conclusion that these must be due to contact-induced developments. However, such a conclusion needs to be substantiated with careful analysis of crosslinguistic data. This approach will be demonstrated with a case study of an innovation in the Lamunxin dialect of the Tungusic language Ėven. This dialect, which is under strong contact pressure from the Turkic language Sakha (Yakut), is developing a purpose clause marker out of a converb of the generic verb of speech which is structurally parallel to a Sakha purposive construction. Notwithstanding the crosslinguistic frequency of this construction, detailed analysis supports the role of contact in its development in Lamunxin Ėven.