Adding global captions to a non-video Storyline course

I have created a Storyline course with 60 slides. Each slide has an audio file. I would like to add captions to each slide.

I've worked on similar projects and have added captions manually; however, I'm hoping there's a better solution. 

If I have one comprehensive VTT file of all narration in the course, is there a way to apply this to the entire course (rather than slide by slide)? 

My course is not a video and is not intended to be a video.