T. V. Raman
Cambr idge ResearchLab
Digital Equipment Corp.
Bldg 650, OneKendall Square
Cambr idge MA 02139
E-mail : [email protected]
Voice-mail : 1 (617) 692-7637
Fax : 1 (617) 692-6650
Ab stract Intro duction
Screen-reader s |computer software thatenable s a vi su-
A screen-reade r i s a computer application de s igned to
ally impaire d us er to read the contents of a vi sual
providespoken fee dbackto a vi sually impaire d us er.
di splay| have b een available for more than a decade.
Screen-readers have b een available s ince the mid-80's.
Screen-reader s are s eparate f rom theuserapplication.
Dur ingthe 80's, suchapplications relie d on thecharacter
Cons equently,they have little or no contextual inform-
repre s entation of the contentsofthe screen to pro duce
ation aboutthe contentsofthe di splay.Theauthor has
thespoken fee dback. The adventofbitmap di splays
us e d traditional screen-readingapplications for the last
le d to a complete breakdown of thi s approach, s ince the
veyears. Thede s ign of the sp eech-enablingapproach
contentsofthe screen were now lightanddark pixels.
de scr ib e d here has b een implemente d in Emacsp eak to
A s igni cant amount of re s earchanddevelopmenthas
overcomemanyoftheshortcomings hehas encountere d
b een carr ie d outtoovercomethi s problem and provide
with traditional screen-reade rs.
sp eech-acce ss tothe Graphical Us er Interf ace (GUI).
Theapproach used byEmacsp eak i s very di erent f rom
The best and p erhaps the most complete sp eech acce ss
that of traditional screen-reade rs . Screen-reade rs allow
system tothe GUI i s Screenreader /2 (ScreenReader For
theusertolisten tothe contentsapp ear ing in di erent
OS/2) developed by Dr. Jim Thatcher atthe IBM Wat-
partsofthe di splay; buttheuserisentirely re sp ons-
son Re s earch Center [Tha94]. Thi s package provides
ible for buildinga mental mo del of the vi sual di splay in
robust sp oken acce ss toapplications under the OS2
order tointerpret whatanapplication i s tryingto con-
Presentation Manager and Windows 3.1. Commercial
vey.Emacsp eak, on theother hand, do e s not sp eak the
package s for Microsoft Windows 3.1 providevarying
screen. Instead, applications provideboth vi sual and
levels of sp oken acce ss tothe GUI. TheMercator pro-
sp eech fee dback, andthe sp eech fee dbackisde s igned to
ject [ME92, WKES94, MW94, Myn94]has fo cus e d on
b e sucientbyits elf.
providingspoken acce ss tothe X-Windows system.
Thi s approachreduce s cognitive load on theuserand
A common feature of traditional DOS-bas e d screen-
i s relevantto providing general sp oken acce ss to in-
readers and sp eech acce ss package s tothe GUI i s their
formation. Pro ducingspoken output f rom within the
attempt to convey the contentsofthe vi sual di splay via
application, rather than sp eakingthe vi sually di splayed
sp eech. In f act, a s igni cant amountofthedevelopment
information, vastly improves the qualityofthespoken
e ort require d tode s ign sp eech-acce ss package s tothe
fee dback. Thus, an application can display its re sults
GUI has concentrate d on building up robust o -screen
in a vi sually pleas ingmanner; the speech-enabling com-
models |a data structure that repre s entsthe contents
ponent renders the same in an aurally pleas ingway.
of the GUI's vi sual di splay. Construction of such an o -
screen mo del helps screen-reade rs regain the groundthey
lost due tothe advent of graphical di splays. However,
Keywords: Sp eechInterf ace, Direct Acce ss, Sp oken
thenature of sp oken fee dback provided does not change.
Fee dback, Audio Formatting, Sp eech as a rst-class I/O