Processing of Logical Expressions for Visually Impaired Users

Although there are many voice systems that can act as user interfaces for visually impaired people, there is still a problem with explaining more complicated structures to these users (such as mathematical equations, logical proofs, chemical formulas etc.) through speech. The output of such an interface is then reduced to a text reader. The problem is that we have lost (graphic) information about the structure, which is 2-dimensional. Within this paper we will describe a solution to this problem. We will concentrate on the structure of expressions and on reading logical proofs. We will present a preliminary design for a new markup language to describe the structure of logical proof and a method of how to present it to users by using speech efficiently.