In children’s acquisition of double-clause constructions, clauses in parenthetical position are special in allowing different interpretations of clause-relationship structure. Children may categorize parenthetical clauses as variants of matrix clauses, adverbial clauses or independent main clauses or as autonomous chunks. Spontaneous-speech analyses of English and German acquisition take internal inflexibility as evidence of chunk acquisition (Brandt, Lieven & Tomasello 2010, Diessel & Tomasello 2001), but inflexibility in parent-child interactions may be inaccurate as chunk-status indicator since these contexts may encourage stereotyped viewpoint talk. The present study uses a kindergarten corpus to compare parenthetical clauses and possible source constructions in Danish. Analyses of distribution, flexibility, pronunciation and formal marking suggest that clauses with parenthetical verbs are used more flexibly in children’s group conversations than in one-on-one interactions with a caregiver. In Danish, the parenthetical construction most likely develops as an extension of the complement-clause construction, supported by children’s schemas for object-first clauses.