The TinyMCE docs mention translations via language files, but I'm not sure how to change a label text with the default (en_US) language.
Seen in the screenshot is the "Link plugin" overlay. Here I want to change the label for "Link list" to "Articles". When inspecting the label in the frontend, I cannot see any specific label markup (key, or name) for this particular dropdown. Does that mean that it might me hardcoded somewhere and I cannot even change it?
Try
tinymce.addI18n('en',{
"Link list": "Articles"
});