Mine is doing this to, after two phone calls with Verizon tech support for my Samsung Galaxy Edge 7.
First resolution that didn't work was clearing the data in a hidden application. It worked initially, but then returned after charging.
Second resolution was to reset the settings (not a factor reset, just the most basic reset of settings). Again, that seemed to work, but I wake up this morning after charging and it's back to repeating the sentences.
I'll be calling tech support again today for help.