This article challenges the theory and practice of the exclusion of the adult learner's first language (L1) by reporting learners' overwhelmingly positive perceptions of its incorporation in foreign language teaching and learning. Classroom-based research was undertaken with university students in an English as a foreign language course which included and incorporated the L1. Upon completion of the course the learner-participants were asked for their perceptions of the experience in written form, this being the data collected. Results of the research demonstrate learners' positive response to the experience in their expressions of how and why they considered that the inclusion of the L1 had been beneficial to their foreign language learning experience. While the focuses of the research were literate Spanish-speaking adults in Mexico and English as the target language, the views of learner-participants expressed in the data concerning the inclusion and incorporation of the L1 in the foreign language learning experience suggest that the practice would be applicable in EFL teaching situations with learners of different backgrounds and/or with different L1s, and in the teaching of other target languages.