Would Saunders and Belgotai be mutually comprehensible with a gap of a thousand years between them?
We are told how English has changed:
Belgotai has a slurring accent although it becomes easier to follow with practice;
vowels sound different;
consonants have been modified;
"r" is more like twentieth century French or Danish;
foreign words, especially Spanish, have been incorporated.
"Chronning," chronology, has also changed. Belgotai does not recognize "nineteen seventy-three."
"...modern chronology dated from the ascension of John Mteza I." (p. 180)
- because the late twenty-seventh century Planetary League and African Dissenters had ended the earlier Armageddonist/Fanatic rule.
Some of this sounds like (a different version of) Poul Anderson's first future history series, the Psychotechnic History.
Onward.