This paper investigates the influence of the mother tongue in vocabulary use in foreign language writing. The lexicon is considered one of the language aspects most permeable by L1 (Arabski 2006). L1 transfer is pervasive in all age groups and L1 backgrounds. Factors such as contrastive relationships between L1 and L2 lexis, or psychotypology evidence differences in lexical transfer. We were interested in describing how the L1 influences lexical production in L2 writing. Moreover, we wanted to examine whether different L1s influence lexical transfer in different ways. We analysed the written production of 71 Spanish and 38 German 4 th graders. Learner compositions were scrutinized for instances of lexical transfer: borrowing or complete language shift, literal translation or calque, transfer of semantic features from L1 to L2 words, and relexification or foreignizing. Linguistic and psychotypological reasons led us to believe that German learners would transfer more, due to the higher perceived similarity between German and English. Results confirmed this hypothesis but only as regards borrowing. The great formal similarity between many German words and their English equivalents is liable to lead learners to these types of transfer. By contrast, calques and transfer of semantic features are more independent of formal similarity, and thus rarer in our data of young, low proficient L2 learners. Zusammenfassung: In diesem Beitrag wird der Einfluss der Muttersprache auf die Wortschatzbenutzung in L2 untersucht. Der Wortschatz wird als einer der L1 durchlässigsten linguistischen Aspekte (Arabski 2006) betrachtet. L1 Übertragung kann in Lernern aller Altersgruppen und L1en wahrgenommen werden. Kontrastive Beziehungen zwischen L1 und L2 Wortschatz oder psychotypologische Aspekte legen Unterschiede in lexikalischer L1 Übertragung offen. Wir waren daran María-del-Pilar Agustín-Llach: Universidad de La Rioja, E ˗ mail: Maria-del-pilar.agustin@unirioja.es EuJAL 2014; 2(2): 287-310 MOUTON Brought to you by | Nanyang Technological University Authenticated Download Date | 6/12/15 4:21 AM María-del-Pilar Agustín-Llach MOUTON Brought to you by | Nanyang Technological University Authenticated Download Date | 6/12/15 4:21 AM