Cultural variations in the commercial correspondence in English

English is considered an international language in the business, the academic and the scientific environment. The English language is used by speakers with different cultural backgrounds who make use of it as a lingua franca; as a consequence, this fact produces a change and variation in the use of the second language. This affects to the teaching of specific business English or English for commercial purposes, that has suffered an important expansion recently. The cultural characteristics of the producer of a second language interfere in the way he/she expresses, and although the language use is correct, there are expressions or formal words that show us the nationality of the writer. In this article, we analyze if the influence of the mother tongue (L1) causes cultural variations in the textual organization of application letters, written in English language (L2) by Spanish students of Business Studies. We evaluate if these variations affect to formal communication in business English or if, on the contrary, the students are not affected by their L1 and follow the instructions of the L2 proposed by textbooks and practiced in class.