Adverb placement is one of the frequently discussed but not yet resolved issues on word order variation. Numerous proposals have been made to explain the order of adverbs and other material based on semantic features or structural requirements. The structural implementation of adverbs in the GB-tradition was made via adjunction. So adverbs undergo a quite free placement in this approach. Others consider adverbs as specifiers of functional heads. This perspective leads to a more restrictive ordering of adverbs but also to a higher amount of functional phrases. Information structure was also assumed to be one important factor: There is a clear preference to separate old and new information by focus sensitive adverbs in German or indicate the topic status of subjects and objects via subject, object < adverb. To sum up: Adverbial positions and their proper interpretation cannot follow from semantics or syntax alone but rather from the interface of these two components. Such interface effects on adverb placement between information structure and prosody are of main interest for the thesis. Results from a corpus study for spontaneous speech and a production task experiment are presented to show a strong correlation between the prosodic prominence and adverb placement in embedded clauses in German. I argue that the pre-focal position for adverbs comes to prevent a stress clash on the phonological phrase level of two lexically headed and therefore informatively enriched phrases, namely subject and object, or object and main verb. The idea for the interface is that the match between syntax and semantics requires a higher prosodic prominence on lexical categories plus the highest prominence for focused constituents. The prosodic structure dislikes stress clashes on different prosodic levels (syllables, words, phrases) and needs a rhythmic alternation, which leads to better contrasts and a faster parsing of information. To satisfy this alternation material can be deaccented or, if possible, reordered. So, the optimal word order for embedded sentences in German is the one with accented lexical phrases (usually subject as topic and object as focus) and a non-accented adverb in-between them.