This article documents a longitudinal study of language attrition in a bilingual girl, who grew up in Germany, and moved to Portugal at the age of 9. The present study aims to analyze effects of language loss in German, the language which was no longer used on a daily basis after return. Data collection started 3 weeks after her immersion in the Portuguese setting and ended 18 months later. Results show first effects of language attrition after five months of reduced exposure to German; 18 months later the informant showed severe word retrieval difficulties and was unable to produce complete sentences in German. The findings, thus, confirm the conclusions of other studies on child language attrition, which suggest that there is a critical period for language retention in childhood
