“This paper is organized as follows. We begin with a brief historical background of mobile and handheld devices. This is important because it juxtaposes the efforts of researchers with the corporations that created early mobile and handheld devices. Following this, we offer some opinions and observations on the evaluation of text input techniques. Many, but not all, of the techniques described later in this paper have been empirically evaluated in user tests. To compare input technologies, the results of these evaluations are crucial. Factors to consider are presented and elaborated. Following this, we detail one of the most active areas of current research – optimisation of text entry using language and motor control modelling. Finally, we present a survey of the current state of the art in text entry for mobile computing. We conclude with some observations on the technologies reviewed and the open research questions that remain.”

Link: Text entry for mobile computing: Models and methods, theory and practice (yorku.ca)