[inkyoto]

> Being a native Spanish speaker, I am accustomed to knowing how a word is spelled just by hearing it, although there are some cases where there might be doubt (like the homophones b and v, or the always silent h) […]

And then there is the double l, «ll», which is pronounced as «y» in nearly all varieties of Spanish. But, yes, the Spanish spelling is far more regular and straightforward compared to many other languages.

> Now, Finnish? It's way, way more regular.

… at this given point in time and history. The relationship between the spelling and the pronunciation is a notoriously complicated affair due languages being living things that keep on evolving with the spelling and pronunciation inevitably diverging over extended periods of time. There is not guarantee that, for example, either Spannish or Finnish will be pronounced the same way in, say, 200-300 years time as they are spelled today.

Different languages with their respective writing systems have resorted to different ways of dealing with the problem. English and Icelandic, for instance, have retained most of the historical spelling representing the no longer accurate historical pronunciation (with some complications), whilst, for example, Tibetan (being one of the more extreme examples) and Burmese languages have retained the archaic spelling in its entirety – both are spelled today using the pronunciation that existed hundreds of years ago. Other languages have resorted to regular historical revisions of spelling rule to purge obsolete spellings or even purge the disappeared sounds, e.g. Russian.

On the opposite side of the spectrum we have Chinese characters that have remained [mostly] unchanged over a very extended period of time, however, the pronunciation has changed several times, i.e. 越 as /*ɢʷaːd/ in Old Chinese -> as /ɦuɑt̚/ in Middle Chinese -> as /yuè/, /yuht/, /yad6/, /oat/, /uêg8/, /hhyq/ in modern Chinese languages (Mandarin, Cantonese, Hakka, Hokkien, Teochew and Wu, respectively).

[int_19h]

However, the languages evolved much faster historically than they do today. On one hand, the states are now effectively enforcing standard forms of language on populations via universal primary education, and then mass culture and media further reinforce that, often aided by social conventions (where the enforced standard often becomes socially proper "educated speech" that people strive to emulate to present themselves better and/or to not be discriminated against). And at the same time, modern borders significantly reduce migration rates, making it harder for language innovations to spread.

I'm not saying that it doesn't happen, of course. But a phonemic spelling created today is still likely to have a much longer useful lifetime than one created 300 years ago, say.