Text Entry Highlighting and Formatting

Hello! I've had an interesting concept requested of me that I'm struggling with. Essentially, we want to have the learner able to enter their own text, and then format it.

So for example, we ask the learner to type a sentence. Then, ask them to highlight a word in the sentence. Then, have them click a button to make it bold.

Is there a way to do this with a text entry field? So far the best I can think of is using drag and drop interactions to simulate highlighting and standard button interactions to bold, but doing all that on custom text would be an issue.

I'm using Storyline 2, but if there's a feature on 3/360 that would help I'm all ears.