Why is English spelling so weird and unpredictable? Don’t blame the mix of languages; look to quirks of timing and technology.
English spelling is ridiculous. Sew and new don’t rhyme. Kernel and colonel do. When you see an ough, you might need to read it out as ‘aw’ (thought), ‘ow’ (drought), ‘uff’ (tough), ‘off’ (cough), ‘oo’ (through), or ‘oh’ (though). The ea vowel is usually pronounced ‘ee’ (weak, please, seal, beam) but can also be ‘eh’ (bread, head, wealth, feather). Those two options cover most of it – except for a handful of cases, where it’s ‘ay’ (break, steak, great). Oh wait, one more… there’s earth. No wait, there’s also heart.
The English spelling system, if you can even call it a system, is full of this kind of thing. Yet not only do most people raised with English learn to read and write it; millions of people who weren’t raised with English learn to use it too, to a very high level of accuracy.