It has been proposed that rare linguistic patterns have high genetic stability and strong resistance to areal influence (Nichols 1992: 181). However, I show that even rare linguistic patterns may be diffused through language contact. Many temporal clause-linking devices (e.g. ‘when’, ‘while’, ‘until’) that are cross-linguistically rare occur in areal clusters, suggesting that language contact has played an important role in their cross-linguistic distribution. The clusters composed of rare features seem to be the result of event-based triggers (inducers), that is, historical events that led patterns to spread due to intensive language contact. In this particular scenario, patterns have been copied not because they have a universally high probability of developing, but out of mere fashion (Bickel 2017). The areality of temporal clause-linking devices is the result of pattern replication. In this scenario, only the patterns of the other language are replicated, i.e. the organization, distribution, and mapping of grammatical or semantic meaning, while the form itself is not borrowed (Heine & Kuteva 2006; Matras & Sakel 2007). Put another way, no phonetic substance is involved but rather the transfer of patterns or structural templates (Kuteva 2017: 166)‎. 

In this talk, I develop a series of methodological steps for investigating the directionality of spread of various temporal clause-linkage patterns: identifying the source and the details of chains of contacts where possible. One of the main findings is that most of the time, speakers of replica languages copy all properties and functions of a clause-linkage pattern from a model language. However, sometimes only some functions of a clause-linkage pattern are copied.