Complex sentence: Perhaps this was due to the hardships of the frontier, dealing with an unfamiliar language and a historically severe winter Cleveland had experienced during their first winter there, as well as failing health led them to this decision.
Split into simpler sentences: Perhaps this was due to the hardships of life on the frontier, dealing with an unfamiliar language and a historically severe winter Cleveland had experienced during their first winter there. These challenges, as well as their own failing health led them to this decision.