How do I book an appointment on a noisy bus?

Give people a usable choice of input and a way to check the answer. Speaking should be an option, not an entry requirement.

Later, you are home with a good connection and would rather speak than type. The centre has tried optional voice with people with varied speech and hearing needs. Its tested version shows editable text, has a clear microphone stop button and only looks up available times.

Which option fits this situation now?

• Let people choose voice while keeping typing and staff help
  Why this choice?

  Optional voice now fits your preference and the tested setting. Keep the words and times visible, allow corrections and stop the microphone when asked. If the connection drops, explain what happened and offer typing or staff help. No appointment is booked by this helper.

• Make everyone use voice because the trial went well
  Why this choice?

  A successful trial does not remove the noisy bus, privacy concerns or different access needs. Keep typing and staff help available without extra hurdles.

• Keep voice unavailable because typing worked on the bus
  Why this choice?

  Typing solved one situation; it is not everyone's easiest route. A tested, optional voice path can help people who prefer speaking without taking typing away.

Offer another way in, not a new requirement everyone must meet.

When would you choose speech, and when would you want the same task to stay silent?

Multimodal access means offering more than one way to interact, such as typing and speaking. People need visible corrections, control of the microphone and an alternative when a mode does not suit them. Audio recording needs separate consent.

Balance conversational speed with correction, privacy and access for users who cannot or do not want to speak.

Accessible service design · 8 minutes

The problem

Synthetic practice scenario: all quantities and evaluation outcomes are illustrative, not reported research. A public information service wants spoken answers about opening hours and appointment availability, without booking or changing appointments in the pilot.

Your initial decision

Which interaction should the first pilot offer?

• Users include people with speech differences, hearing loss, shared-device privacy concerns and unreliable mobile connectivity.
• No representative speech evaluation exists yet; a provider demo used quiet-room speech only.
• The service must offer keyboard and text access, visible answers and a human contact route.
• Audio retention is off by default; any research recording requires separate informed consent and a deletion policy.

Compare the alternatives

• Offer opt-in streaming voice alongside the text service

  Streaming can reduce turn-taking friction while preserving text access and microphone controls, but untested interruption handling and weak connections may create confusing partial turns.

• Add push-to-talk with editable transcripts

  Explicit turns and correction reduce conversational fluidity but expose recognition errors before the answer is used, with clear microphone activation and cancellation.

• Launch text-only while evaluating representative speech tasks

  Text avoids untested audio processing but postpones benefits for people who prefer or need speech input.

Mechanism, trade-offs, and evidence

• Start with access to correct information, not humanlike conversation; speech input and speech output are independently optional capabilities.
• An editable transcript helps users correct recognition, but it is not a reason to remove other input methods.
• Evaluate task completion with relevant users and conditions while minimizing collected audio and explaining its use.
• Treat WCAG as accessibility requirements to implement and assess, not a badge conferred by choosing a speech provider.

Reconsider after a change

Consented usability trials and independent task checks now support an optional streaming conversation mode on qualified connections, while weak-network users still need the existing path.

What should the service change after these results?

• Illustrative trials cover 60 consenting participants across the pilot's speech and hearing access needs; they do not establish performance for all populations.
• On qualified connections, the synthetic 2-second response-start target is met and all tested interruption and correction tasks pass; weak connections still miss the target.
• The streaming path performs only read-only information lookup, with visible transcripts, a microphone indicator and a working stop control.
• Text, push-to-talk and human support remain available without extra hurdles; audio storage remains opt-in and purpose-limited.

Compare the alternatives

• Keep push-to-talk as the default in unqualified settings

  Explicit turns sacrifice some speed but remain easier to correct where connectivity or user preference does not fit streaming.

• Keep the release text-first while broadening speech research

  Further recruitment could uncover missing access needs and simplify the immediate release, but defers an optional mode already supported for the qualified pilot group.

• Add opt-in streaming with immediate fallback

  Qualified connections gain faster turn-taking, while cancellation, connection checks and parallel accessible paths add maintenance.

Mechanism, trade-offs, and evidence

• Change the recommendation because representative, task-specific interaction evidence improved, not because a provider announced a better speech benchmark.
• Keep the tested scope narrow and distinguish response-start latency from full task completion and correctness.
• Use ongoing feedback to find unrepresented access needs and regression cases, without claiming the finite pilot proves universal accessibility.
• Provide an understandable fallback when quality drops; silence, stuck playback or an invisible mode switch is not graceful recovery.

Related technical concepts

Follow-up lessons retain their existing sign-in and plan requirements.

• real time voice agents
• multimodal perception
• edge agent
• human in the loop patterns
• agent ethics

Technical sources

• Web Content Accessibility Guidelines (WCAG) 2.2 — W3C

  Provides requirements for accessible web interaction and alternatives; a voice model benchmark alone cannot establish accessibility conformance.

• Demystifying evals for AI agents — Anthropic Engineering

  Explains tasks, graders, repeated trials and outcome evaluation for agents; use task-specific tests rather than importing reported scores.

• Building effective agents — Anthropic Engineering

  Distinguishes fixed workflows from model-directed agents and recommends testing simpler solutions first; its tooling examples are historical.

Explore the technical decision