"scribal whims from over 1000 years ago (some, month, love), or 550 years ago (read now, read then), or the spelling mistakes committed by printers in the 15th and 16th century because they spoke no English (friend, ghost) and the dictates of one deranged man (rabbit - habit), " Masha, tell me more! My y6 class would love this.
It's a long story and I don't want to break any MN rules by giving u links to any of my stuff.
In brief:
Early scribes did not like short, downward strokes next to each other (e.g. sum, munth or luu - there was no v in ealy English) so they changed u to o.
Adding an extra e and doubling a consonant was a common practice for padding out lines (in - inne, word - worde, shop - shoppe) by early printers.
Most were got rid of again by the pamphleteers of the English Civil War (1642-9) because they wanted to squeeze the maximum of information onto a page, but quite a few still survive (e.g. relative).
The royal scribes did weird things with English spelling when they had to switch from using French and Latin to English after 1430 (end of 100 yrs war with France), like introducing ea for /e-e/ and /e/, e.g. 'treat threat' for earlier 'trete thret/thrette'.
The biggest messing up of English spelling occurred after the publication of Tyndale's New Testament (1526). Its many editions were printed abroad, by people who spoke no English, because possessing an English bible was illegal for laymen in England until 1539. People bought them anyway and learned to read and write with their different spellings. For most people, it was the first and only book they owned.
Tyndale lived in hiding on the Continent. He was hanged and burnt at the stake in 1536 for transalting the whole bible into English.
Because Sam Johnson had far greater respect for Latin than he did for English, he made some changes, such as Shakespeare's 'cittie/citty', 'pittie, pitty' to 'city' and 'pity'. If a word had no doubled consonant in Latin, he liked to drop in English.