In this article we report two studies: a detailed longitudinal analysis of errors in "wh"-questions from six German-learning children (age 2 ; 0-3 ; 0) and an analysis of the prosodic characteristics of "wh"-questions in German child-directed speech. The results of the first study demonstrate that German-learning children frequently omit the initial "wh"-word. A lexical analysis of "wh"-less questions revealed that children are more likely to omit the "wh"-word "was" ("what") than other "wh"-words (e.g. "wo" "where"). In the second study, we performed an acoustic analysis of sixty "wh"-questions that one mother produced during her child's third year of life. The results show that the "wh"-word "was" is much less likely to be accented than the "wh"-word "wo", indicating a relationship between children's omission of "wh"-words and the stress patterns associated with "wh"-questions. The findings are discussed in the light of discourse-pragmatic and metrical accounts of omission errors.