The problem isn't Chinese in general, but the written register of Chinese specifically, and all the texts already using it. If you've ever looked at a verbatim transcript of a spontaneous conversation, you'll probably have noticed how much of an incoherent mess spoken language can be. Written speech is much tidier, because people have the opportunity to be very deliberate in what they write down.

For Chinese in particular, that means that people can be much more succinct in writing than orally, because the characters provide additional disambiguation beyond just indicating the pronunciation. Any purely phonetic writing system would require everyone to readjust their standard of what kind of sentences are comprehensible.

DeFrancis book The Chinese Language: Fact and Fantasy is excellent on that and many related questions [1].

First, Mandarin has no inflection (love/loves), which allows for writing in characters in the first place. Then, Mandarin has a fairly impoverished phonetic system, allowing for only about 400 different syllables ignoring tones, or 1200 or so when distinguishing tones (while English for example has some 7000 or so, without tones). This leads to many homophones, which can be distinguished by being written with different characters. Or so the traditional justification goes (I don't think much of that argument, because clearly people can speak to each other just fine, without having to clarify which word they mean - disambiguation happens by longer words (two or more syllables), which you could just write down. What happens is that in writing, you only need to write parts of a word: spoken out loud it would be ambiguous, but the chosen character disambiguates it, and thus people conclude that writing wouldn't work without the characters.)

However, arguably it's just a matter of habit (and resistance on the part of those that have already put in the time and effort to learn the characters). There are, in fact, Sinitic languages written alphabetically, eg Dungan [2].

The whole issue is very politicised, as you can see with the animated discussion here and the vigorous resistance to the initial comment (which was a bit unfortunately phrased, in my view, but fundamentally sound: Chinese is a very hard language to learn, mostly by virtue of its archaic writing system, and that is arguably somewhat deliberate.)

[1] https://en.wikipedia.org/wiki/The_Chinese_Language:_Fact_and...

[2] see the articles linked from here: http://languagelog.ldc.upenn.edu/nll/?p=40417

>just a matter of habit

That's a vast understatement. Adopting a writing system that would render everything written in the formal register incomprehensible isn't exactly a tenable position.

Europeans used to write in Latin, which is now incomprehensible to most, and yet, it has all worked out.

But granted, the transition took a while and was not just a matter of habit.

Having said that, why could one not publish important classic texts in a phonetic vernacular version, and leave the study of the originals to those with the inclination (just as most people in the West do not learn Hebrew, ancient Greek, and Latin; yet can find versions of the Bible, Euclid, Seneca, and Newton that they can read if they so desire.)

You're drawing a false analogy here, the problem isn't that phonetic writing isn't capable of rendering classical texts; the problem is that they can't competently render any text written in the formal register.

So, here we get to the fundamental issue then: Chinese seems to have a larger divergence between spoken and written register than most other languages (particularly alphabetically written ones).

It's unclear to me how far that extends. (This issue seems intertwined with the issue that many speakers of other Chinese "dialects"/"languages" also use Standard Written Chinese (ie Mandarin), btw.)

It is possible to write some register of Chinese in phonetic writing, though - that's shown by Dungan (written in Cyrillic), by the experiments in the 30s (quoting Mao again: "we have begun experimenting with Hsin Wen Tzu—Latinized Chinese. It is now used in our Party school, in the Red Academy, in the Red Army, and in a special section of the Red China Daily News."), etc.

Characters can be mapped to their phonetic equivalents no?

Yeah, but not back (in other words, a mechanical mapping won't preserve sufficient information to disambiguate). It's definitely not trivial.

But they can't be mapped back.

Yes, that something is homophony. Mandarin has 1522 syllables when you include tone (413 syllables without). [0] English has 15,831. [1]

[0] https://chinese.stackexchange.com/questions/14596/how-many-s... [1] http://semarch.linguistics.fas.nyu.edu/barker/Syllables/inde... [via wayback: https://web.archive.org/web/20091115065840/http://semarch.li...]

Chinese characters are syllabic.