We approach all verbal tasks with certain expectations having to do with the linguistic form of utterances in context. Speech interfaces are no exception, and the design team should regard them as conversations. Dialog designers and prompt writers should take advantage of the fact that everyday conversation is the communication system most familiar to our users. We occasionally encounter resistance to conversational prompt design on the grounds that spoken language is thought to be inherently inferior, careless, or too relaxed for the customers of Company X. In these cases, prompts that lack contractions or everyday cohesion devices are endorsed under the rubric of "better writing." But conversational language is a sophisticated system of its own, having developed for reasons of its own. Better prompting is not a question of "better writing" in the traditional sense. Unlike written language, spoken language has evolved from prototypically face-to-face interactions over the course of millions of years. Spoken language incorporates features and principles that are specially adapted for this mode of communication and that we should observe and exploit in prompting. To leverage users' familiarity with spoken language, we make the following recommendations, based on observations of the form of naturally occurring language:
Successful prompt writing depends on a view of the VUI as much more than a mechanism for collecting information via acoustic signals. A user-centered speech application is really a language interface, where "language" implies both a cognitive dimension (e.g., use of cohesion devices, principles of information structure, and pointer-word directionality) and a social dimension (e.g., jargon, vocabulary and grammar choices, and register). VUI designers who are mindful of these dimensions of linguistic experience are well on their way to creating a VUI that will engage users and project a favorable corporate image or persona. It is also of paramount importance to consider the form of prompts in context. A prompt is not a simple, isolated translation of a recognition return, such as <action GET_QUOTE>, or "Too Much Speech." Every prompt is like a small piece of tile in a mosaic, in that the whole is perceived as greater than the sum of the parts. When you write prompts, always consider the context of the dialog, because the structure of naturally occurring language is itself context-sensitive. Context sensitivity is what listeners expect, whether they are participating in a human-to-human conversation or an engineered dialog. Conversational language is one of Mother Nature's greatest masterpieces. Prompt writers and dialog designers should regard it as a source of inspiration for user-centered design, tempered with an awareness of the limits of the current technology. |