For those in the early stage of learning a foreign language, they commonly experience difficulties in understanding spoken words in the second language, while they have no problem in recognizing words spoken in their mother tongue. This paper examines this phenomenon using biomimetic receptive fields that can be interpreted as a transfer function between acoustic stimulus and cortical responses in the brain. While receptive fields of individual subjects are often optimized to recognize unique phonemes in their mother language, it is unclear whether challenges associated with acquiring a new language (especially in adulthood) is due to a mismatch between phonemic characteristics in the new language and optimized processing in the system. We explore this question by contrasting biomimetic systems optimized for four different languages with sufficiently different characteristics. We perform English phoneme classification with these language- optimized systems. We observed distinctive characteristics in receptive fields emerging from each language, and the differences of English phoneme recognition performance accordingly.