The first Japanese immigrants arrived in Brazil in 1908 establishing Japanese communities around the country in order to preserve the Japanese culture and language. The social and cultural environment had great influence on speech patterns during the process of language integration, as described in Kuyama (1999). The purpose of the present study is to analyse the linguistic challenges observed in the speech patterns of first generation of Japanese immigrants in two communities in Brazil, Aliança and Fukuhaku-Mura. Contact between Japanese and Portuguese languages allowed the development of two main speech patterns derived from bilingualism: lexical borrowing from Portuguese and code-switching, which are the object of the study. The present study will try to identify the phonetic and morphological challenges in the speech of first generation Japanese immigrants through analysis of the dialogues from Gardenal (2008). The results showed that there are still phonological integration challenges with phonemes and syllable structure that do not exist in the Japanese phonological system. The morphological integration of the Portuguese verbs follows the same pattern as that of the English verbs with the addition of the verb suru ‘to do’ to the verb. However the Portuguese verbs are conjugated in the third person singular while the English verbs are kept in the infinitive form. The verbal and nominal agreements present errors due to the lack of gender and number in the Japanese grammar.