Test a complete task, not just the play key
A player may respond to a keyboard shortcut for play while leaving its caption menu inaccessible. The practical check is a complete task: reach the player, identify the focused control, open the caption choices, select a track, return to playback and leave the player. W3C's keyboard guidance covers access to interactive controls and avoiding a focus trap.
Use the keyboard commands documented for the browser, assistive technology and player. Do not assume every site uses the same letter shortcuts. A shortcut can also be intercepted by another application or a screen reader mode. Record the actual sequence and environment so that a failure can be reproduced without guessing which control owned the keystroke.
Make focus evidence understandable
Visible focus helps sighted keyboard users know which control will respond. Accessible labels help assistive-technology users identify its purpose. A report can distinguish a control with no visible focus from one with an unclear name and from one that cannot be activated. These may share a symptom of difficult operation but require different website corrections.
If a screen reader is part of the setup, give its name and version along with the browser and operating system. You do not need to disclose a diagnosis or personal medical history. Describe the input method and task requirement. The website operator needs the interaction evidence, not a private explanation of why a person uses the keyboard.
Retest the whole route after a fix
After an update, repeat the original sequence through caption selection and back to the surrounding page. A button gaining a label is helpful, but the full task may still fail if focus is lost when the menu closes. Verify that the selected track actually appears and that the viewer can continue operating the page.
Keep the conclusion proportional: the tested browser and keyboard route can now select the named caption track and leave the player. This does not establish every accessibility requirement or every assistive-technology combination. It does give a clear, useful result that a general statement such as accessible player cannot provide on its own.
Questions answered
Does a working spacebar shortcut prove the player is keyboard accessible?
No. Test the complete functions you need, including settings, alternative tracks and leaving the controls.
Must I disclose a disability when reporting a keyboard failure?
No. The input method, environment, sequence and observed obstacle are the useful technical details.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.

