Presentation: accessibility support levels by language

[mitchellevan]

After a couple of months of playing with content, this picture is taking shape.

• All devices, user agents, and ATs support (example: English)
• Some ATs do not support for the AT UI
• Some ATs do not support for reading content
• Some devices or user agents do not support for UI
• Some devices or user agents do not support for reading content
• Some devices do not support for writing content
• No direct support in the in-scope user technologies