A couple of typos/grammos:

* "Allow to turn accessibility features on and off..." should be something like "Accessibility features can be turned on and off with keyboard shortcuts"

* "simultanous" -> "simultaneous".  (Although it's not clear to me what "simulate simultaneous keypresses" actually means.)

* "Allow to control..." (Mouse Keys tab) should be something like "Pointer can be controlled with the keypad"

* It's slightly disconcerting that "Toggle Keys" isn't mentioned in the top level dialog any more, even though the feature is available.  Users who rely on this feature may assume that it's not implemented, but we'll just have to wait and see on that, I guess.

Other notes:

* The "General" heading isn't really needed, suggest just removing it and left-align the checkbox with the bold labels below it.   (Any label called "General" should set alarm bells ringing, as it's basically information-free.)

* Suggest changing the label of the "Notifications" button to something like "Audio Alerts" or "Audio Feedback", perhaps with the addition one of the stock sound icons -- in desktop parlance, "notification" tends to refer to the panel notification balloons from libnotify. 

* Mouse keys: checkbox label doesn't need to be in bold, it's not acting as a group header in this dialog.