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 |
|
Text-to-speech function | Built-in text-to-speech function with preferred languages |
Variable speed playback |
|
Additional features |
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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.
16Table 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. |
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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