This article investigates the acquisition of the focus particle "auch" "also" by German-learning children. We report data from spontaneous and elicited production of utterances with the focus particle "auch" by 1- to 4-year-olds complementing earlier findings of a delayed production of the unaccented "auch" compared to the accented one. But in contrast to previous studies showing that children have problems interpreting sentences with accented and unaccented "auch", we found indications for adult-like comprehension in an eye-tracking experiment by children from 3 years on. These results reflect early availability of adult-like linguistic competence with respect to both "auch"-variants which does not always lead to adult-like performance. This variation in children's performance across tasks is considered to be due to additional modality and task specific constraints. Development in this area thus reflects not a change in underlying knowledge, but rather a change in the constraints on its behavioral manifestation. (Contains 9 figures and 7 footnotes.)