If there is no full keyboard, like on a phone, then voice recognition may be necessary for inputting into forms and search strings. Chieko Asakawa found browsing the Web somewhere between difficult and impossible using today's Windows screen readers. Home Page Reader was released as an IBM product in Japan in October of 1997. IBM Special Needs Systems in Austin picked it up and has been adapting it to the North American blind user, adding recommended access features, and aspects of HTML 4.0 support. A blind user needs to be able to open a URL, read a page, stop, hear short segments again, continue, hear a link, follow that link, listen again and fast forward through the un-important parts.
Sighted users get that from visually scanning the page.
The display is two dimensional with colors and images. So it is sort of two-plus dimensions. Speech is one dimensional. We can add voice changes and pitch changes, just as color is added to the screen. Voice changes kind of make it one-plus dimensions.