While reading The Case of Charles Dexter Ward, a story by H.P. Lovecraft, I came across passages that are intended to read as letters written around 1750/1760. The first of these begins as follows:
Prouidence, I. May (Ut. vulgo)
Brother:
— My honour’d Antient ffriende, due Respects and earnest Wishes to Him whom we serve for yr eternall Power. I am just come upon That which you ought to knowe, concern’g the Matter of the Laste Extremitie and what to doe regard’g yt. I am not dispos’d to followe you in go’g Away on acct. of my Yeares, for Prouidence hath not ye Sharpeness of ye Bay in hunt’g oute uncommon Things and bringinge to Tryall. I am ty’d up in Shippes and Goodes, and cou’d not doe as you did, besides the Whiche my ffarme at Patuxet hath under it What you Knowe, that wou’d not waite for my com’g Backe as an Other.
(from "H. P. Lovecraft: The Complete Fiction" by H. P. Lovecraft)
The letter goes on from there, same style. Written in 1927 by Lovecraft, this is not an original document of course. However, the author probably tried to imitate the way people wrote during that period of time, though I couldn't tell exactly how "authentic" he managed to sound.
Thinking about this while trying to decipher the letters (English is not my first language, plus the spelling is pretty messed up) made me question: How did people learn to write on the 17th and 18th centuries? And more than that, were there any grammar standards back then? It seems that different people words in different ways/however they thought it was right.
What we see in old documents is the result of writers being barely literate and committing mistakes or of a lack of grammar standards?
Spelling only starts to standardise with the spread of print, and even in the 17th century, much handwritten English is still spelled phonetically. The very first English dictionary was published in 1604, although the first dictionary to have widespread cultural impact was Samuel Johnson's 'Dictionary of the English Language', published in 1755.
Given that this isn't a real document we will ignore it.
English as we know it today is a real mix of a lot of different languages (including but not limited to Anglo-Frisian, Mercian, Brittonic,Norse, West Saxon and Latin.) Different parts of Britain had different ethnic majorities, leading to differences in dialects, spelling and speech patterns.
Rather than viewing old documents as barely literate, we should consider them as highly educated. It was not uncommon for mere traders to be multilingual.
Some words and spellings are different to how we would view them now, but they follow grammatical structures and make sense in context. English as a language continues to evolve and is ever changing.