My PhD-dissertation deals with prosodic effects on phonetic reduction in Icelandic and their interaction with lexical frequency. A selection of ten adverbs containing the suffix -lega will be studied drawing both on a corpus analysis and an experimental study. The prosodic variables in question are the tendency of Icelandic towards an even rhythm (eurhythmy) and the position of the adverb relative to the nucleus accent. In addition, it will have to be seen whether prosodic effects are equally strong for high-frequency as for low-frequency words.