System and IINA version:

• macOS 13.6.3
• IINA 1.3.4

Expected behavior:
Where appropriate labels presented to the user are localized.

Actual behavior:
In IINA's settings on the Subtitle tab in the ASS Subtitles section the Override level setting is controlled by a slider and has a label that displays the slider value as a string. This value is always shown in English. This setting is tied to the mpv sub-ass-override option:

--sub-ass-override=<yes|no|force|scale|strip>
Control whether user style overrides should be applied. Note that all of these overrides try to be somewhat smart about figuring out whether or not a subtitle is considered a "sign".

• no: Render subtitles as specified by the subtitle scripts, without overrides.
• yes: Apply all the --sub-ass-* style override options. Changing the default for any of these options can lead to incorrect subtitle rendering (default).
• force: Like yes, but also force all --sub-* options. Can break rendering easily.
• scale: Like yes, but also apply --sub-scale.
• strip: Radically strip all ASS tags and styles from the subtitle. This is equivalent to the old --no-ass / --no-sub-ass options.

This also controls some bitmap subtitle overrides, as well as HTML tags in formats like SRT, despite the name of the option.

IINA is missing support for the scale value. That will be a subject for a separate issue.

Steps to reproduce:

• Open the and click on System Settings…

• Click on the General tab

• Under General click on Language & Region

• Scroll down to the Applications section

• Add IINA and select a language other than English

• Start IINA

• Click on Settings… (in the languge being used) under the IINA menu

• The settings panel appears

• On the left side of the panel click on Subtitle

• In the ASS Subtitles section look for the slider

• Move the slider and notice the value displayed is in English

• MPV does not have this problem.

mpv does not support localization.

How often does this happen?
Every time.