The role of phonology in bilingual word recognition has focused on a phonemic level especially in the recognition of cognates. In this study, we examined differences in metrical structure to test whether first language (L1) metrical structure influences the processing of second language (L2) words. For that, we used words of Romance origin (e.g., reptile, signal), which both German and English have borrowed extensively. However, the existing metrical patterns are not identical nor are the borrowed vocabularies the same. Rather, those identical words differ systematically in their foot structure. We conducted a cross-modal form fragment priming EEG experiment (auditory–visual) with German native speakers who were highly proficient in English. Both behavioral and ERP results showed an effect of the native phonology and the loan status, that is, whether the loan exists only in the speaker's L2 or is shared across languages. Priming effects (RTs) were largest for nonshared loanwords indicating some interference from German (L1). This was also evident in a reduced N400 but only if the metrical structure aligned with German patterns for Germanic words, that is, two light syllables as in pigeon. If the words exist in both languages, metrical structure also mattered shown by the modulation of different ERP components across conditions. Overall, our study indicates that metrical phonology plays a role in loanword processing. Our data show that the more similar a word is in terms of its metrical phonology across L1 and L2, the more effortful the processing of a word within a priming paradigm indicating interference from the L1 phonology.