"Caps <word>" - Type with an initial capital
"Caps On" - Start typing words with initial capitals
"Caps Off" - Start typing words without initial capitals
Try "All Caps Off <word>" as well.
I am however running into folk that can't accept this is buggy.
Samsung S6 Android Voice to Text Capitalizes ENTIRE word, regardless of keyboard
When I dictate example: I am not going to the store..
It comes back as I am NOT going to the store
Does not matter if I use Samsung or Swiftkey keyboard nor which email or the stock messenger app