I have a native speaker Canadian lady...well experienced in ADR on mainstream , she does an ADR and narratives for my adult stuff...very nice voice, yet she will NOT do any " uhh ahhas" ...
I do not pay her per word, but per scripted page. Your typed 1000 words ( about 4 pages) equals about 20 pages scripted dialogue or narrative. So by my calculation is what she charges for an average 80 page script divided by 4..... so about 250 dollars per/ 1000 words with no residuals, but as " work for hire"..... let me know if we are in the ball park and I will talk to her ( she does not hang around here
).
BTW : I do all in my sound both at the studio , there is no charge for that since she is a friend.