Just follow these steps on your PlayStation 4:
1. Set a checkmark in Video Playback Settings > Display Closed Captions.
2. Closed Captions Settings appears, and you can set attributes such as the size and background color of text.
3. To display closed captions, press the OPTIONS button during content playback, and then select Control Panel > Closed Captions.
Please note that 3D content is displayed in 2D when closed captions are displayed.