There is a need to re-conceptualise learning for the mobile age, to recognise the essential role of mobility and communication in the process of learning, and also to indicate the importance of context in establishing meaning, and the transformative effect of digital networks in supporting virtual communities that transcend barriers of age and culture.
In this paper we offer a framework for theorising about mobile learning, to complement theories of infant, classroom, workplace and informal learning. A related aim is to inform the design of new environments and technologies to support mobile learning, since the work described here has been developed through a series of projects to design mobile learning technology.
In the tradition of Activity Theory we analyse learning as a cultural-historical activity system, mediated by tools that both constrain and support the learners in their goals of transforming their knowledge and skills. We separate two perspectives, or layers, of tool-mediated activity. The semiotic layer describes learning as a semiotic system in which the learner’s objectoriented actions are mediated by cultural tools and signs. The technological layer represents learning as an engagement with technology, in which tools such as computers and mobile phones function as interactive agents in the process of coming to know.
These layers can be prised apart, to provide either a semiotic framework to promote discussion with educational theorists to analyse learning in the mobile age, or a technological framework for software developers and engineers to propose requirements for the design and evaluation of new mobile learning systems. Or the layers can be superimposed to examine the dynamics and co-evolution of learning and technology.

The framework described in this paper is a step towards an integrated theory of mobile learning that could inform both the analysis of learning in a mobile world and the design of new technologies and environments for learning. We describe learning as a labile process of ‘coming to know’ through conversation in context, by which learners in cooperation with peers and teachers construct transiently stable interpretations of their world. Learning is mediated by knowledge and technology as instruments for productive enquiry, in a mutually supportive and dynamically changing relationship. The mediation can be analysed from a technological perspective of human-computer interaction, physical context and digital communication, and from a human perspective of social conventions, community, conversation and division of labour. These two perspectives interact to promote a co-evolution of learning and technology. We suggest that the implications of this re-conception of education are profound. It describes a cybernetic process of learning through continual exploration of the world and negotiation of meaning, mediated by technology. This can be seen as a challenge to formal schooling, to the autonomy of the classroom and to the curriculum as the means to impart the knowledge and skills needed for adulthood. But it can also be an opportunity to bridge the gulf between formal and experiential learning, opening new possibilities for personal fulfilment and lifelong learning.