Question about "Video Language " in Video Settings?


I Love YTtalk
When uploading a new video, or well editing one I suppose too, where it asks for "Video Language" to be chosen in the Advanced Settings page, does it mean the language as in Audio / Speaking? or is it meaning Text and Writing on the video also?

For example, one of my videos doesn't have and speaking in it and there is no words in the backing audio track either, its just a tune that plays over the video. But at the end of the video, I have text on the screen and English annotations, etc.. So do it put "English" for the video setting? or "Not Applicable"?
Same question... Are there any answer? What is "Not Applicable" at Video Language setting? Does choosing this reduce views? I dont have speaking in video just music and some writings in english. So what should I select the language, English or Not Applicable?

(I translate title and description many other languages, but this Video Language option confusing me)

thank you