This contribution discusses findings and hypotheses from empirical data of naturally-occurring codeswitching. The discussion is framed by some comparisons of the approaches of contact linguists and psycholinguists to bilingual production data. However, it emphasizes the relevance of naturally-occurring codeswitching to the theoretical questions asked by psycholinguists. To accomplish this, relevant grammatical structures in codeswitching are exemplified and analyzed. Analysis largely follows the Matrix Language Frame (MLF) model, but differing approaches are mentioned.