This article presents the results of extensive research focused on a state of the art investigation of translation between Catalan and Spanish both from the Translation Theory and Linguistics perspectives. Due to the detail and length of the study, results will be presented in two separate independent articles. The first one, entitled: “La investigación sobre la traducción entre catalán y español: estudios lingüísticos,” reviews all the research done in the field of Linguistics. The second one, entitled “La investigación sobre la traducción entre catalán y español: estudios traductológicos,” will soon appear in this journal, and will present research done on Catalan-Spanish translation in the field of Translation Studies. The aim of the first article is to provide researchers with an initial approach to the study of Catalan-Spanish translation from perspectives grounded in the field of Linguistics. Linguistic approaches focus on the phenomenon of interference and its implications on the standardization of orthography and grammar in both languages, particularly in Catalan, and also on lexical refinement during the normalization process. Attention will be paid to studies where the impact of Catalan-Spanish translation is relevant to this process. This article reviews grammatical and stylistic approaches, approaches based on synchronic descriptive linguistics, diachronic contrastive linguistics, lexicography, second language acquisition and contact languages.