History of English, the Great Shift of 1850s?

Learning to learn from Ngram Viewer I couldn't help noticing a pretty obvious change of paradigm in some aspects of the language that seems to have taken place around the middle 1800s:

a lot of formerly analytical forms of Degrees of Comparison of Adjective 'all of a sudden' tended to become synthetic. ?t least in those cases where the trend clearly changed. To mention just a few most vivid examples where the crossing point of the graphs falls exactly around 1850s:

quieter over more quiet

https://books.google.com/ngrams/graph?content=quieter%2Cmore+quiet&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Cquieter%3B%2Cc0%3B.t1%3B%2Cmore%20quiet%3B%2Cc0

simpler over more simple

https://books.google.com/ngrams/graph?content=simpler%2Cmore+simple&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Csimpler%3B%2Cc0%3B.t1%3B%2Cmore%20simple%3B%2Cc0

busier over more busy

https://books.google.com/ngrams/graph?content=simpler%2Cmore+simple&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Csimpler%3B%2Cc0%3B.t1%3B%2Cmore%20simple%3B%2Cc0

and even 'to tell the truth' over 'to say the truth':

https://books.google.com/ngrams/graph?content=to+say+the+truth%2Cto+tell+the+truth&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Cto%20say%20the%20truth%3B%2Cc0%3B.t1%3B%2Cto%20tell%20the%20truth%3B%2Cc0

Should it be discarded as just a coincidence or is there a connection to some language phenomenon that I should be aware of?

Thanks in advance,

YETY