COMPOSITIONAL approaches to mobile accentuation of the Indo-European type derive the accent of words from the lexically specified accentual features of their constituent morphemes, together with the BASIC ACCENTUATION PRINCIPLE (BAP), which erases all accents but the leftmost one, and assigns an accent to the left edge of an unaccented domain.1 I propose here a compositional analysis in which BAP is a phrase-level process and stems default to the right by the OXYTONE RULE. I argue that zero grade ablaut is sensitive to the accents erased by the BAP, and therefore applies before it. In agreement with most compositional analyses, I distinguish between DOMINANT and RECESSIVE derivational suffixes. 2 COMPOSITIONAL approaches to mobile accentuation of the Indo-European type derive the accent of words from the lexically specified accentual features of their constituent morphemes, together with the BASIC ACCENTUATION PRINCIPLE (BAP), which erases all accents but the leftmost one, and assigns an accent to the left edge of an unaccented domain.3 I propose here a compositional analysis in which BAP is a phrase-level process and stems default to the right by the OXYTONE RULE. I argue that zero grade ablaut is sensitive to the accents erased by the BAP, and therefore applies before it. In agreement...