coollector.com

for a single video
(Plus Icon) Click to add a video from scratch > Language bar > add video language
Here we can add more than one video language (example; English, French etc.)

But when we add multiple video files from a folder
Tools> scan your video files > select folder > add the recognized files > language field will be set as

Here we can't add more than one video language.

In the future, my plan is to extract automatically all the technical details from the video files: the languages, the subtitles, the resolution, etc... Asking for the language at the end of the scanning is a temporary measure, I know it's sub-optimal.