“…The impact that the student's first language has on their learning and acquisition of any grammatical issue is, on the contrary, a well known fact, as it is the basic hypothesis underlying the pedagogical dimension of Contrastive Analysis (Fries 1945;Lado 1957). However, as it is presented in this volume, it sheds new light on such premise for two main reasons: first, because its connection with the acquisition of TAM in second languages has not been deeply studied (but see Collins 2002;Izquierdo & Collins, 2008;McManus, 2019;Nishi & Shirai, 2019;Slabakova, 2000, among others); and secondly, as a consequence, because the first and second languages it correlates (Russian/Spanish, Dutch/Spanish, Catalan/English, among others) have not been deeply examined from this perspective within this field.…”