One difference is that Rome fell and the Normans brought a highly changed Romance language with them into England. While Korea and China had an ongoing relationship going back millennia. As Chinese changed over time different words from different eras also crept in to the language.
On top of that, Korean itself also changed, harmonized dialects, dropped and added sounds and features and other things. The Korean written in the first book on Hangul by King Sejong the Great is both not only not pronounceable by modern Koreans, but less understandable than Chaucer might be to modern English speakers.
Chinese language was introduced mostly between 4th and 7th centuries [1]. Japanese had no writing system at that time, so they adopted Chinese ideograms (hanzi) and vocabulary, but changed the pronunciation to fit the much (much!) simpler Japanese phonetics. They also started to use the ideograms for words that already existed in Japanese, with their Japanese reading. That's why Japanese ideograms (kanji) have two kinds of readings: Chinese readings (onyomi) and Japanese readings (kunyomi). To make it even more complicated many kanji have multiple readings, and you have to learn which to use depending on the context or the word it's part of.
Later some ideograms started to be used purely for their phonetic, ignoring the semantics, to better match Japanese grammar. With time these ideograms were simplified and they became two different syllabaries: hiragana [2] and katakana [3]. These are not ideograms, but letters that represent a full syllable. Hiragana is used for grammar particles, to spell out kanji and for some words. Katakana is used for borrowed foreign words, or sometimes as a sort of "italics", to emphasize words.
[1] https://en.wikipedia.org/wiki/Chinese_influence_on_japanese_... [2] https://en.wikipedia.org/wiki/Hiragana#Table_of_hiragana [3] https://en.wikipedia.org/wiki/Katakana#Table_of_katakana
European, Language, Littered, Roman, Latin, French, Spanish, Italian, Descended, Imagine, Empire, Existed, Modern, Era, Influence, Sinitic, Asian
"Roman" terms in modern day English.
Also, it's quite common for languages to be written in scripts originally developed for completely unrelated languages. Maltese is related to Arabic but written in the Latin (English) alphabet, Mongolian uses Cyrillic (Russian), Thai/Lao/Khmer derive from South Indian scripts, etc.
This is true, though newspapers and some other written texts make use of mixed hanja-hangul script (hanja honyong) where Chinese characters (Hanja) are interspersed with Hangul in the same piece of Korean text in order to disambiguate homonyms.
Interestingly, you could argue this is attempting to solving the flip-side of the problem that Furigana in Japanese solve (where a reader may know the phonetic reading of a word but not the Kanji that are used to write it -- though native-level Japanese speakers don't need Furigana to read the vast majority of text since Kanji represent more conceptual information than Kana).
Sort of as an example, educated persons in what is now Tajikistan formerly used the arabic/persian derived script. Tajik is mututally intelligible with the Dari spoken in Kabul and is a dialect of Persian. Most of the area was historically part of the greater persian empire at one point in time.
After the Russian influence and Soviet Union grew much stronger, the education system in Tajikistan was forcibly switched to using the cyrillic alphabet to write down the sounds of spoken Tajik Persian.
Now there is a movement to revert to the Farsi writing system as is used in Afghanistan.
But they are quite similar for this example:
Korean: Eumsik dimibang (like 'Eyumsik dimeebong')
Mandarin pronunciation: Yinshi Zhiweifang (sort of like 'Yinshur Jurwayfong')
Cantonese pronunciation: Yamsik Jimeifong (like 'Yumsik jimayfong')
Korean Hanja (chinese character - 汉子) words mostly had their taken pronunciation taken from Middle Chinese. Modern Cantonese preserved more Middle Chinese pronunciation than modern Mandarin.
Also, Japanese kanji (汉子) often have both onyomi (foreign) and kunyomi (native) readings, where the onyomi pronunciation comes again from Middle Chinese.
For example, 电话 (telephone):
Japanese - denwa Mandarin - dian hua Cantonese - dinwa (like 'deenwa')
As a Chinese speaker, Korean very much sounds closeish and Japanese is often similar enough to realize a distant split.
It is important to remember that all branches of a tree grow. China has thousands of dialects all co-evolving and we don't know which the others could have split from and how far either has changed
Korean uses many Chinese loan words (in the same way that English uses Greek loan words) but the sentence structure, pronunciation and grammar are totally different. You would not say English is a dialect or branch of Greek for the same reason.
I speak both Korean, Japanese and am currently studying Chinese. Korean does not sound like Mandarin at all because it is not a tonal language. It does sound similar to Mongolian and Manchurian. That is not surprising because the roots of Koreans (and probably their current language) come from the area north of Korea near Manchuria.
There is a controversial theory that Korean, Mongolian, and Machurian, are all a part of an Altaic superfamily — along with Japanese, Turkish, and a number of others. This was broadly accepted fifty years ago, and less so today.
Mongolian phonology doesn't sound like any other East Asian language I've heard: https://www.youtube.com/watch?v=OkU9Zd0LQjg
That may have been 500, 1000, or more years ago and each continuously absorbed neighboring language features from trade or due to local social structures.
This is why many of the words sound Chinese (and a particularly old version of Chinese).
For example, Chinese has no system of verb conjugation, whereas Korean and Japanese both do, conjugating for the past and present, among other aspects. Chinese also does not have a system of adjective inflection, whereas Korean and Japanese do. Adjectives in these languages inflect to indicate speech level as well as to indicate tense (which is to say, adjectives have a "past form", kind of like verbs).
There are many other structural differences of note.
Beware of arguments based on things we don't know, technically "argument from ignorance". That we don't know which one they might have split from is no reason to believe that this is actually happened! What we don't know didn't happen can't go in place of what we do know did happen.
Another language origin could have been nomadic peoples to the north traveling across the Eurasian steppes, and frankly I'm more inclined to believe that's where Korean and Japanese actually originate from. However, despite the growing study of these peoples that have been neglected in traditional Chinese historiography, they don't leave behind enough archeological evidence for us to prove something like the Altaic language family convincingly, so we're back to null hypothesis and cultural assumptions.
When we look at the grammar of Chinese, Japanese and Korean, it raises a lot of doubts about the possibility of lineal descent -- about the idea that Japanese and Korean are a kind of Chinese. These differences provide positive support for the idea that Chinese bears no especially close relationship to the other two, while discouraging the idea that they are close descendants. Evidence is often like that: supporting what is true while disconfirming what isn't.
My point is that what the "unsupported hypothesis" is depends on your cultural viewpoint. It could be that "not descended from Chinese" is the unsupported hypothesis if you grew up in an environment where most things you experience are descended from Chinese.
Or as another example, if we got into a discussion about whether the sun will rise tomorrow, it's expected that I would have to prove that sun won't rise tomorrow instead of proving that the sun will rise tomorrow. There's no evidence either way until tomorrow arrives. But our baseline assumption is that the sun will rise tomorrow because that's what it's done every prior day. Our null hypothesis are informed by everyday experience, and that's very much a part of our cultural background.
The unsupported hypothesis in argument from ignorance doesn't have to be any particular hypothesis, or a culturally supported hypothesis. Argument from ignorance is a way to frame any hypothesis for which we're not offering positive evidence in a speciously credible way.
P2: "I don't believe this is true" (because my background assumption is that things originate from China)
P1: "What evidence do you have that Korean isn't independent of Chinese"
P2: "None, we have no evidence from this time period."
P1: "Therefore, Korean has an independent origin from Chinese."
P2: "That is argument from ignorance."
P1: "Here are differences between Korean and Chinese."
P2: "I don't believe this is sufficient evidence to enough to revise my doubt about your hypothesis." (because of the strength of my belief in my background assumptions)
What I'm pointing out is that P2's background assumptions and strength of belief in such is inherent to his culture and life experience. This could have easily gone
P1: "Korean has an independent origin from Chinese."
P2: "Okay" (because my background assumption is that things have independent origins.)
Or in an alternate universe
P1: "Korean originates from Chinese."
P2: "Okay" (because my background assumption is that things originate from China)
Where P1 offers some discussion of differences between Korean and Chinese, that's where we start to get into a discussion based on evidence that can be evaluated. If P2 doesn't find it convincing, then we can ask why; this allows P2 to muster evidence which can be evaluated. That's a fine and constructive direction. A finite conversation like that doesn't necessarily end with a solid conclusion and everyone being convinced of the same thing.
What you're pointing out with regards to the perceived strength or weakness of certain assumptions is not what we're talking about with argument from ignorance: argument from ignorance is about the form, not the semantics.
They are not. The languages must have come first / evolved independent of China, and then a wave of foreign commerce / scholarly / government influence over centuries propagated Chinese writing to them.
So the spoken language uses Chinese based characters to record the sounds in writing, but it may not necessarily have relation to what the sounds are in Chinese if someone were to read the characters as if Chinese. And the spoken language is not at all related to Chinese (aside from some imported words). As if someone encountered English alphabet words being spoken with totally different sounds assigned to them.
That was very interesting to finally understand -- if I've even gotten it all correct...