I'm sorry if I don't have a cut and dry answer for you! It learns the best it can from what you type, so it really depends on being consistent with whatever diction and syntax you end up using.
My guess is you probably won't get great results if you repeat words in that way (because then it has to infer left or right based only on the "space" character between the words, which probably is not the only place you use spaces).
For practice, as far as I know it won't matter -what- you practice, as long as you know the result you want to practice and it 100% succeeds at it. But you can certainly experiment with it, this is new technology, and a new kind of gameplay! We aren't certain of the optimal strategies either! XD