In this paper, we briefly describe the limitations of present CALL systems, caused both by technological factors and by the limited agenda of CALL developers, whose design goals tend not to result in software tools for practical everyday language learning activities. We also note the lack of creative new ways of using computers in language education and a gradual shift towards traditional teaching and learning practices, enhanced with common computer technologies such as multimedia content delivery systems and social media. However, computers can provide more options for interactive learning, as shown by the emergence of virtual labs or virtual sandboxes that support and encourage open experimentation. Such systems are well known in natural sciences, but still have had little impact on the world of CALL software. We believe that the same “free experimentation” approach used in natural sciences can be applied in CALL, and should have a positive impact on the quality of learning, being consistent with constructivist perspectives on language education. In the present paper, we briefly introduce our work-in-progress to develop a system that supports open experiments with words and phrases.