Software engineers can use various techniques to elicit relevant information from stakeholders to specify the requirements that a software-intensive product must satisfy. However, few are aware of the differences and advantages they have from each other. This article presents an exploratory study of the vision that requirements engineers have on twelve requirements elicitation techniques. An empirical study has been carried out using two classification techniques: card sorting and repertory grid. The perceptions obtained with each technique were compared, showing that there are differences and coincidences in the visions captured by each technique. This study can help guide training objectives on software requirements and conduct future empirical studies that show the adequacy of each elicitation technique.