Key features

While there are no minimum technical and functional standards for screen readers, we outline applicable sections from: (1) The WHO-UNICEF Assistive Product Specifications (APS) for audio book players (see table 6); 14 (2) Web Content Accessibility Guidelines (WCAG) that govern accessibility of web content (see table 7); and (3) Accessible Rich Internet Applications (ARIA), geared to enhance the accessibility of web content for people with disabilities (see table 8).

Table 6: WHO-UNICEF Assistive Product Specifications: Selected functional requirements for audio book players

Feature Standalone/Tabletop Audio DAISY Player
Audio formats AAC (audio), AMR-WB+, FLAC, MP3, Ogg Vorbis, Speex, WAV
Digital document formats
  • DAISY 3.0 and EPUB 3 text-only books
  • DAISY 2.02 TOC only audiobooks
  • DAISY 2.02 and DAISY 3.0 full-text full audio synchronized books
  • docx, doc, html, and txt files
Text-to-speech function Built-in text-to-speech function with preferred languages
Variable speed playback
  • Slow down to 75 per cent or less
  • Speed up to 200 per cent or more
Additional features
  • Internet connectivity for content transfer and firmware update
  • Optional: Built-in camera or compatible with external camera and built-in optical character recognition

Note: Standalone/Tabletop Audio DAISY Player apply to audio players with Digital Accessible Information System (DAISY) capability. Advanced audio coding (AAC); Extended Adaptive Multi-Rate – Wideband (AMR-WB+); Free Lossless Audio Codec (FLAC), MPEG Audio Layer III (MP3); Waveform Audio File Format (WAV).

Available guidelines, research, and evidence around screen-reader user needs and preferences can be used to define a set of key features that would characterize a user- friendly screen reader interface.

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Table 7: Selected technical and functional features for screen readers

Key features Description
Text-to-speech conversion Allow users to adjust speech rate, volume, and preferences.
Navigation commands Provide keyboard commands for efficient element navigation.
Braille output Support refreshable Braille displays for tactile feedback.
Annotations and descriptions Include descriptive information for non-text elements.
Compatibility with AT Ensure integration with other assistive tools.
Customization Allow users to customize settings for a personalized experience.
HTML mark-up Use semantic HTML for better screen reader interpretation.
Alternative text Provide descriptive alternative text for non-text content.
Keyboard compatibility Ensure keyboard navigation for users relying on-screen readers.
Visually led content Make web content understandable without visual cues.
Dynamic content Avoid automatic carousels. Allow user-controlled interactions.
Accessibility overlays Test overlays for compatibility with screen readers.
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Table 8: Screen reader-friendly interfaces

Key features Description
Large touch targets Design touch targets to be easily accessible on mobile devices.
Limited links Minimize links in banners to enhance navigation efficiency.
Skip links Provide skip links for quick access to essential page sections.
Short paragraphs Use short paragraphs to aid screen reader users in content comprehension.
Adequate (sub-)headings Structure content with clear headings for easy navigation.
Coded headings Follow HTML specifications; use correct heading levels.
Alt-text for images Provide descriptive alt-texts for images for accessibility.
Careful with modals Ensure modals receive focus for accessibility. Test thoroughly.
Avoid CAPTCHAs Avoid using CAPTCHAs. Consider alternative security measures.
Follow coding standards Use standard components. Adhere to coding standards for accessibility.
Test with a screen reader Familiarize yourself with screen-reader usage for effective testing.

Important parameters in the quality of screen readers include the number of tasks that can be performed and user-friendliness of the software. Examples include user-friendliness to install and navigate the software; multiple language support; voice recognition; integration with Braille displays; ability to perform tasks in word processing, spreadsheets, and presentations, e-mail, web-browsing, videoconferencing, or PDF applications. Multiple language support is still limited across many technologies, and language-coverage gaps remain for specific functionalities such as text-to-speech (TTS).

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