Actually, that ancient document was in surprisingly good condition, even after Kirk’s somewhat rough handling, so it’s not a matter of combining word fragments. The illiterate Yangs merely slurred the words really, really badly over the centuries.
I watched the episode earlier, and as TWDuke pointed out the documents were in great condition. So I guess it’s just a matter of the Yangs being illiterate (biting tongue, lest I make a political commentary) and slurring the words.
I had the satisfaction of correcting a few minor errors of fact on the Wikipedia page on this one - the previous writer claimed that Kirk didn’t have “We the people…” memorised, whereas the actual problem was that Cloud William pronounced it so badly that Jim couldn’t pick up the cue.
Now let’s imagine that this turkey had been the second pilot instead of Where No Man Has Gone Before - as it could well have been…