Translate "Load More/Loading..."

I’ve followed the instructions on how to translate the plugin with good results first using Translatepress, and later switching to “Say What”. And while almost all content worked without any problems, neither of them was able to translate the portfolio button to load more content. Which says “Load more” until you press it, upon which it switches to “Loading…”

So, how can I change this to my preferred language? I didn’t find it in the code either, but might have missed it if it’s in one of the java script files?