Turkish expresses adverbial subordination predominantly by means of converb clauses. These are headed by nonfinite verbs, i.e. converbs, which have a converb suffix attached to the stem. The different converbs express different aspectual relations between the subordinate and the superordinate clause, and they can be modifying or non-modifying. We analyse data from speakers of Turkish as a heritage language in Germany and the U.S. as well as monolingual speakers of Turkish in Turkey. The data come from two age groups: adults and adolescents. We show that unlike in canonical Turkish, converbs in heritage Turkish can be multifunctional, meaning that they can express both simultaneity and causality, for example. Furthermore, we show that converbs in heritage Turkish can be both modifying and non-modifying. As possible factors which might be responsible for such variation, we discuss language contact, sociolinguistic differences between the speaker communities (Germany vs. the U.S.) and age of the speakers.