A yearlong study of the acquisition of German by three American secondary school students reveals influence of orthographic input on their segmental development in phonology. The three had not been exposed to German prior to the year they spent in Germany, they received little explicit instruction on German, and they were the only native English speakers in their communities. Examination of their production of word-initial <s>, which is realized as [z] in German but [s] in English, points to influence of the orthographic input they received while interacting with written text as fully matriculated students in German secondary schools. Despite considerable aural input from their standard German-speaking peers, teachers, and host family members over the 12 months of their stay in Germany, the three learners’ production of word-initial <s> was typically [s]. Finer-grained analysis using Praat shows variation in voicing, suggesting these learners were also responding to the aural input.