SR Telephony Applications. Designing Speech-Only User Interfaces

Transcription

1 SR Telephony Applications Designing Speech-Only User Interfaces

2 Overview Types of Services Designing Speech-Only Applications Feedback and Latency Prompting Strategies Handling Errors Usability Testing

3 Automated Telephone Services Recorded Announcements DTMF Applications Bank balance inquiries Flight schedules The growth of Internet has shifted attention to customers accessing information and services through the Web

4 New Generation of Services Information Retrieval E-Transactions Stock quotes, news, traffic Stock trading, package tracking, account status Telephone Services Intranet Unification Voice routing, personal voice dialing Inventory, Corporate Portals mywhatever: Personal Portals, Agents

5 Voice Interface Functionality Basic IVR C: For stock quotes, press 1. For trading, press 2. H: (presses DTMF 1 ) Basic Speech IVR C: Say the stock name for a price quote. H: Lucent Technologies Advanced Speech IVR C: Stock Services, how may I help you? H: Uh, what s Lucent trading at? Near-Natural Language C: How may I help you? H: Um, I would like to get the current price of Lucent Technologies. C: Lucent is up two, at sixty eight and a half. H: OK. I want to buy one hundred shares at market price. C:

6 Design for Speech Not effective to add speech to an existing graphical application or to translate it directly into a speech one Vocabulary used by people when talking to one another, is different than that used by the application Information organization and presentation is different Speaking menu commands is awkward, a more natural interaction is necessary

7 Design for Speech (Examples) Dates Monday, June 12 th 2000 (Absolute Dates) A week after tomorrow (Relative Dates) Reading Inbox contents Three, Hilda Binda, Change of Address Message 3 from Hilda Binda is about Change of Address Performing program actions Move, Weekly Reports File this into my Weekly Reports folder

8 GUIs versus Voice-UIs Long lists of items are tedious when read by a speech synthesizer Terms used in menus and options of GUI differ from spoken vocabulary Calendar applications use absolute dates while people use relative dates Menus make functionality visible to user, something not clear in speech applications There is no possibility of misrecognitions of commands in a GUI

9 Design Challenges Even by designing with speech in mind from the outset, certain challenges are presented by the use of speech Transience: What did you say? Invisibility: What can I say? Asymmetry Speech recognition performance Speech synthesis quality

10 Designing Speech-Only Applications (1/3) Feedback and Latency Processing delays insert confusing pauses Speech is a slow output channel Need for feedback on actions Implicitly verify commands that present data Explicitly verify commands that destroy data or trigger actions

11 Feedback and Latency (Examples) The user needs to know the current state Still processing or waiting for input? If heard, was speech correctly interpreted? Explicit feedback Do you want to make a payment of $1,000 to Boston Electric? Say yes or no. Implicit feedback Tomorrow s weather forecast for Boston is

12 Designing Speech-only Applications (2/3) Prompting Achieve best trade-off between flexibility and performance. Less options better recognition Explicit prompts constrain user Implicit prompts allow flexible input Taper prompts to make them shorter Incremental prompts speed interaction (expert users) and provide help (naïve users)

13 Prompting (Examples) Explicit prompts Say cancel, send or receive Implicit prompts Send mail to Bill Did you mean Bill Gates or Bill Clinton? Taper prompts Start recording after tone. Pause for a few seconds when done Record after tone, then pause Record then pause Incremental prompts Which service? (pause) Say banking, or address book

14 Designing Speech-only Applications (3/3) Errors can be found by the user or the interface Rejection errors Do not repeat error messages for errors in same sentence Progressive assistance Reprompt more explicitly Misrecognitions and misfires Filter recognition results Allow for correction of a portion of the input

15 Handling Errors (Examples) Progressive assistance What?, then Sorry, please rephrase and finally Still no luck. Speak clearly but do not overemphasize Explicit prompts and constraint grammars Yes/no questions Prompt user to press a key as an alternative to speaking Filter recognition results Schedule meeting for 3am, probably an error Correct portion of input Tomorrow s weather for No, I said Tuesday

16 Involving Users Natural Dialog Studies Ask target users to talk with each other while working through a scenario Wizard-of-Oz Studies A human wizard simulates the speech interface Usability Studies Assess how well users are able to carry out the primary tasks of the application