3 Background

Emacspeak was originally developed in late 1994 and released as Open Source in May 1995. Since then, the system has been regularly updated every six months to provide an up-to-date Audio Desktop. Here is a brief overview of some of the significant aspects of the system, and the lessons learnt from its development and use. The work on Emacspeak was presented at CHI96 and the co-located Assets96 conference in Vancouver, BC. This overview is being written nearly 15 years later to trace the impact of the work.


3.1 Speech-Enabling Applicationss

The underlying thesis behind AsTeR (Audio System For Technical Readings) and later Emacspeak is that information is display-independent. This leads to the insight that producing auditory renderings of information starting from the true source of that information often produces better renderings than those that result from working from a modality-specific representation; thus, attempting to speak visually rendered information can often prove suboptimal. AsTeR applied these ideas to documents authored in LaTeX; Emacspeak generalized these ideas to user interfaces.

Emacspeak was therefore designed from the ground-up to enable applications generate their own spoken feedback, rather than having an external software program construct the spoken feedback by responding to events in its environment.

In Emacspeak, theory meets practice to deliver a working implementation; Emacspeak leverages the power of Emacs and its embedded Lisp interpreter to inject spoken feedback into applications that run within Emacs. For a detailed overview on how the advice mechanism in Emacs is used, see the original Assets96 paper, as well as the chapter on Emacspeak in the OReilly publication entitled Beautiful Code.


3.2 Audio Formatting And Aural CSS

AsTeR introduced the notion of audio formatting a concept analogous to the well-understood notion of visual formatting. The work on AsTeR coincided with the Web being at its infancy. As the Web evolved to acquire Cascaded Style Sheets (CSS), ideas from AsTeR were used to define Aural CSS as an appendix to CSS1 in 1995. Emacspeak proved an ideal platform to prototype the ideas within Aural CSS — first within the Emacs/W3 browser. Around this time, Emacs itself evolved to support multiple fonts and font-locking to implement syntax coloring for various types of content. Emacspeak applied the ideas of audio formatting to create the auditory analog of font-lock — Emacspeak calls this voice locking.

Voice locking in Emacspeak continues to be a unique feature among systems that provide auditory feedback. Later in 1997, Emacspeak’s implementation was overhauled to use Aural CSS for all aspects of voice-locking, rather than just for Web content.


3.3 Auditory Icons

Emacspeak augments spoken feedback with short auditory icons that vastly speed up interaction. Combined with audio formatting, the resulting experience is analogous to moving from a monochrome character-cell display to a high-quality color display — the overall user experience is rich in comparison. This enabled Emacspeak to explore innovative means of auditory communication — as an example, see my Assets-98 paper entitled Conversational Gestures For The Audio Desktop that details how one can play Tetris on the Emacspeak desktop.


3.4 Summary

The lessons learnt from developing Emacspeak are many — here are a few highlights:

And many more than will fit this margin.


This document was generated on August 4, 2026 using texi2any.