Activate Siri and just on't use it. When you want to type, tap the microphone and go from there. Yes, still uses Siri servers, but in my experience it is infinitely more reliable than having Siri look things up for you.
You can use things like Dragon, as mentioned, but those aren't integrated into your keyboard. They essentially have you rely on copying and pasting from one app to the other. Unless you are reciting paragraphs at a time, this saves you no time at all.