Abstract: This paper examines the mobile vocabulary learning practice to discover how far mobile devices characterizing portability and mobility are being used to support vocabulary learning. An activity-centered perspective is undertaken, with the consideration of new practice against existing theories of learning activities including behaviorist activities, constructivist activities, situated activities, collaborative activities and informal and lifelong activities. Such an approach allows one to reflect on what mobile learning has to offer L2 vocabulary learning and to hypothesize what features of this technology use are likely to change how languages are taught and learnt. The integration of mobile devices and vocabulary learning needs to take into consideration portability, social interactivity, context sensitivity, connectivity and individuality. Insights gained from such a perspective will inform researchers and teachers of emerging vocabulary learning practice and its potential relevance to innovation in language learning.