Most of people agree that making mistakes is a part of learning, others think of mistake as a problem, but ... what is a mistake? Why do we make them? Can we learn a language without making mistakes? Do we need a teacher to correct all mistakes we make? Is it useful?

This paper´s aim is to clarify these questions, analyse mistakes students make when learning a foreign language, and present different techniques how to correct them. Moreover, it focuses on the common mistakes Spanish students make when speaking English. It also discusses the causes of these mistakes.

This paper consists of two parts. The first one is theoretical and it is based on general information about mistakes and the second part focuses on mistakes Spanish students make as well as on the causes of these mistakes. This part also includes exercises and recommendations how to avoid or correct these mistakes.