This paper examines the view that parentheticals obligatorily form an intonational phrase and break up the intonational phrase of the matrix sentence into two intonational phrases. The analysis of spontaneous speech data of Hamburg German shows that neither do all parentheticals form a distinct intonational phrase nor do all parentheticals break up the intonational phrase of the matrix sentence. The most frequent type of prosodic integration is prosodic parenthesis, which is the insertion of one intonational phrase into another and parallels parenthesis on the syntactic level. Additional analyses reveal that the size of the parenthetical and the syntactic integration of the parenthetical into the matrix sentence affect its prosodic integration. Finally, it is argued that the distinction between syntactic and prosodic parenthesis can solve common problems in defining parentheticals.