I can actually explain the French one!
Back in ye olde days before the printing press everything you wanted 2+ copies of had to be copied by hand. So there were these people, known as “copiers”, who would, well, copy stuff.
Most kings paid by the word, but not the French king. He paid by the letter.
So, naturally, the copiers were like “Fuck it, let’s go nuts” and just stuffed half the alphabet into every word to make some extra cash.
Also, in contrast, no letters in Latin are silent. This is because things were often inscribed on stone, meaning ain’t nobody got time to waste on carving out letters that aren’t being used.
So Latin may have 7,638 different tenses and moods, but at least you know how to pronounce what’s written.
First of all, most “silent” French consonants are not actually silent. They’ve been assimilated into the vowels that precede them, and re-appear when followed by another vowel. In linguistics, this process is called ‘Liaison.’ The s in ‘les’ is the easiest example of this. ‘Les chats’ is pronounced ‘lay shah;’ but ‘les enfants’ is pronounced ‘lez enfan.’ That isn’t a pointless letter thrown in by overenthusiastic copyists; it’s a letter that is pronounced conditionally, in order to break up similar sounds. English has this too; consider how, in American English, the h at the start of the word ‘herb’ is only pronounced if the sound preceding it was a vowel.
Some ‘silent’ French letters, by contrast, actually modify the sounds the vowels make themselves. Like that second n in ‘enfants.’ Any French speaker would find it ridiculous if you suggested that ‘enfants’ and ‘enfats’ would be pronounced the same way. The n alters the a in the second syllable. This process is known as Cheshirization: when a sound that is no longer pronounced itself can still be ‘heard’ by its influence on the sounds surrounding it.
French spelling too reflects the history of French speakers (like every language). Certainly, Latin as spoken by the people in Rome had no silent letters; but in the region of what is now France, these relatively recent converts to the Latin language were used to pronouncing things they way they had been pronounced in Gaulish. We unfortunately don’t have many records of Gaulish, but what we do know tells us that Gaulish speakers habitually dropped unstressed syllables. Gaulish also made a lot of use of Assimilation – when sounds start to sound more like the sounds surrounding them, like how “handbag” is actually pronounced “hambag” – and Lenition, which is when consonants are softened unless they are needed to break up other sounds: think of how ‘wait’ is actually pronounced “way–.” The t isn’t silent, but it’s soft and sonorous and maybe inaudible to the ears of non-native English speakers.
Modern French is full of assimilated sounds, soft and musical consonants, and dropped unstressed syllables, simply because the Gauls would have had no reason to start pronouncing words in a completely new and alien way just because they were learning a new language. These things are, essentially, the linguistic archaeological footprint of the ancient Gaulish accent.
I’ve never heard this story about French copyists throwing in extra letters to make some extra coin off the French king (which king?), and 10 minutes of Googling it with different keywords and combinations didn’t turn up anything. The introduction of printing in 1470 did necessitate some spelling reform, but it was a standardization effort; they didn’t add ‘more letters,’ that would have only made printing more expensive and time consuming.
During the 18th century, French orthography was reformed to be much clearer and simpler, with a number of defunct, silent letters done away with altogether. For example, estre (the verb to be) became etre. Accents, which had been used by printers for centuries, were formally adopted, in order to clarify the pronounciation of vowels and vowel clusters. The letters V and J were also adopted into the French alphabet, where before they had been confusingly indicated as a consonant form of U and I. So, ‘uil’ became ‘vil’ (vile). This significantly reduced the number of homonyms the French had to contend with (that is, words that are spelled the same but mean different things).
Smaller reforms have been introduced to French orthography intermittently ever since, with the most recent push of note happening only in 1990. Among the changes made was the abolition of a silent t at the end of a bunch of words (leveraut became leverau, etc), the trema diacresis (the two dots that you put over some vowels to indicate that they are NOT silent) was moved in order to be simpler to understand, and the circumflex (the pointy hat that goes over some vowels) was gotten rid of anywhere it wasn’t necessary anymore.
IN OTHER WORDS, the authorities responsible for simplifying and streamlining French spelling have done their best with an ancient, beautiful, messy language which is – it really needs to be stressed – far more regular in its pronunciation than English.
What kind of confusing bastard language makes cough, through, dough, and tough all sound completely different, honestly.