These are the most important language leaming theories: -The Cognitive Cede theory is based on the ¡dea that the rules of the language are leamt consciously. -The Natural Approach believes that the mother tongue and a second language are leamt in the same way. -The Audiolingual theory claims that language is nothing but a set of habits. -The Communicative leaming theory claims that the most effective way of leaming a new language is by using it to communicate. -The Humanistic theory is based on the idea that language is used to develop human beings. As research about second language leaming confirms the complexity of the process, we should not rely exclusively on only one of these theories. We have to look for a new theory that includes the best aspects of all of them. In order to look for this new theory, this paper describes some of the techniques teachers can use with their students to gather data for research. Advantages and disadvantages of each one of these techniques are discussed.