[jimworm]

> Rather, written Cantonese (or Shanghainese etc.) often use characters for phonetic purposes rather than true etymological meaning

This is where the mistake is. Written Chinese does have all those characters - it is the adoption of a "standard Chinese" that caused those characters not to be taught when mass education was introduced. The people were left to transliterate or create new characters for their spoken native tongue, and the correct characters are now known only to researchers.

One very annoying part of Mandarin's effect on modern Chinese is that many words are being replaced by transliterations of/in Mandarin, even when the Chinese word itself exists. Often this is because the source of the word was foreign. To a non-Mandarin speaker, written Chinese is very slowly turning into complete nonsense, and written Chinese is losing its edge in longevity by no longer being a ideograph-based language.

[CorrectHorseBat]

Chinese was never an ideograph based language to begin with. Yes, most characters have that somewhere in their origin, but there's so much corruption, change of meaning and borrowing of sound going on all through history that you really don't get anywhere using ideographs.

Example in Mandarin: 我不知道 : I don't know. But in ideographs: weapon flower root arrow mouth foot head.

[ncmncm]

It has been a very, very long time since written Chinese was a substantially ideograph-based language.

It is amazing how many literate Chinese people think of it as one.

[jimworm]

That's merely refuting the least relevant part.

The ideographs were important in that they could tie together vastly different spoken languages in the same family. Because the writing was unified, all the spoken variants had their own influence on it by way of traders and administrators, and successful changes by proxy affected the speech of other regions. This meant that all the different places effectively evolved their languages around a virtual core based on the communications of the literate class - even the phonetic-based parts; and they could do it peacefully and continuously, constantly realigning their definitions without legal or violent coercion, uninterrupted by the constant evolution of the whole group of spoken languages.

For example, French has had a great influence on English, and they both use the Latin alphabet. Would such influence have been possible in the same time without violent conquest, given the alphabetic system of writing?

[CorrectHorseBat]

Do you have any literature backing this up? It all sounds like pseudoscience to me, but I could be wrong.