The bilingual mental lexicon is understood as a unified system containing word forms from multiple languages. Previous studies have described how cross-language phonological similarity influences bilingual lexical processing, demonstrating that lexical activation spreads both within and across languages at the segmental level. The significance of cross-linguistic phonological neighbors in bilingual speech processing is well documented, but less is known about frequency effects emerging from the cross-language neighboring words. In monolingual spoken word recognition, the 'neighborhood frequency effect' suggests that higher-frequency neighbors absorb more activation and/or inhibit lower-frequency neighbors within a phonological neighborhood, potentially affecting recognition latencies. This study examines whether this effect extends across languages in phonological neighborhoods of late German-English bilinguals. Results reveal that lexical frequency rates of German neighbors influence response times for English target words in an English lexical decision task. This finding supports a fully integrated mental lexicon in late bilinguals (i.e., second language learners) and highlights the role of lexical frequency in cross-language lexical processing.