A table read is a quick way to judge pacing, catch stiff or repetitive dialogue, and hear whether your characters sound like different people. Screencake now has one built in: Table Reads.
There are two kinds of voice. Your Mac's own voices work out of the box and are the lightweight option, but they can sound flat. Natural voices sound like a cast. They are a one-time download of about 365 MB that runs on your own computer, and nothing you write is sent anywhere.
Natural voices are opt-in. Let us know what you think.
Happy writing.