aizie:
English is spelled phonemically; each phoneme in a word is represented by a discrete spelling. The act of teaching how the phonemes of a language are represented by a symbol is 'phonics' regardless of how transparent or opaque the language's orthography is.
That is not what is normally understood by 'phonemic'.
Children in countries with transparent orthographies still need explicit phonics instruction, though they will clearly master the necessary knowledge and skills much sooner and may find it much easier to generalise.
They do. And they learn to read and write faster, precisely because they can generalise. For reading, they can generalise with absolute certainty, because o, ou, ch or whatever always have the same sound, unlike in English (on, only, once - sound, soup, southern or chat, character, chalet).
In English being taught the main alternative pronunciations, like (mean - meant, children - child, home - come) does make it a bit easier to access words - if u have some idea what the word might be. This is less useful with words that have a different sound in only a few words (our - your, four, tour, paid - said, plaid, plait). - There should be controlled research in how best to teach those.
In learning to spell English, there is much less scope for learning general rules (or generalisation). It involves vastly more word by word memorisation of different spellings than any other alphabetically written language, especially for the sounds that don't really have a main pattern at all,
such as the 452 words with an /ee/ sound,
156 of which use ea, 133 ee, 86 e-e, 29 i-e, 31 ie, 15 ei (eat, meet, even, police, siege, seize)
- 13 odd bods (people, ski, key, he).
That's why it takes so long and why lots of people never quite get to grips with them all.