German root and subordinate clauses are in almost perfect complementary distribution with respect to the placement of the finite verb. In root clauses, the finite verb canonically appears immediately after the first constituent, and such clauses are called 'verbsecond' (V2). Subordinate clauses, in contrast, canonically have their finite verb as the last element, and are called 'verb-last' (VL). However, much research indicates that under certain conditions, subordinate clauses can be uttered in V2 shape. V2 in complement clauses occurs in two variations, here termed 'nullV2' and 'dassV2', illustrated below: (1) Dirk meint, Lara ist schwanger. (nullV2) Dirk claims, Lara is pregnant. (2) Dirk meint, dass Lara ist schwanger. (dassV2) Dirk claims, that Lara is pregnant. The present study uses psycholinguistic techniques to investigate several proposals in the literature concerning the semantics and pragmatics of German complement clauses. Specifically, the study tries to answer the following questions: does V2 word order and/or the presence of the complementizer dass mark a complement clause as a proposition asserted by the speaker? In other words, are the complement clauses in (1) and (2) interpreted as propositions asserted not only by Dirk, but also by the speaker? Twenty-seven native speakers of German participated in a reaction-time study in which they read sentences similar to those in (1) and (2), as well as sentences containing canonical complement clauses (termed 'dassVL' clauses). In one task, they responded to yes/no questions about the truth of the proposition in the complement clause (e.g., ist Lara schwanger, 'is Lara pregnant?') and estimated how certain they were about their answer. In a second task, participants made grammaticality judgments about sentences similar to those in the first task. Responses, certainty estimations, and response times were not significantly affected by word order. All three types of clauses yielded frequent 'yes' responses and high certainty estimations. However, word order did have a significant effect on grammaticality judgments: contrary to recent findings, dassV2 clauses were judged as less grammatical than their nullV2 and dassVL counterparts. These findings suggest that neither V2 word order nor the presence of the complementizer mark complement clauses as speaker assertions.