The focus of this paper is on unusual developmental structures during the simultaneous acquisition of German and English in early childhood, which were evident parallel to a majority of target structures. The aim is to explain the cognitive motivation for unusual acquisition structures as well as the eventual retraction from them. I will show that they support the contentions of the Competition Model that language acquisition proceeds through orientation to surface structures and that cue competition across languages changes the weighting of cues within the language. The retreat from non-target structures was made possible through the children's attention to contrasts between the languages and the need to resolve structural incompatibilities within the language.