The fairy had a kid's voice, but its wording was as if it was an adult.
That worker's clear diction gives me a good impression.
I was surprised by how much my friend's language had changed in the time since I'd seen him.
Remember how 言葉 means "language?" Well when you add つき to the end of it you end up talking the whole time the moon (つき) is out and paying more attention to your own speech and wording.
The readings for this word are both kun'yomi readings. You've learned both of these readings by now so you should be able to read this on your own.