I would put phrasal verbs in the same category as learning vocabulary - it's something you acquire over the long term, gradually. The added difficulty is that the verb and the preposition can be separated and also sometimes the ambiguity between a standalone preposition and a preposition that is part of the verb.
Another thing you only learn through exposure, if that, is what "sounds natural" over and above being grammatically correct. And idioms, too. And sometimes even after many years you still get caught in idioms such as "I hear you" vs. "I can hear you" (this happened to me once not so long ago, to general hilarity). When the capital development of a country becomes a by-product of the activities of a casino, the job is likely to be ill-done. — John M. Keynes
Then toss in the American/English differences and things can get sticky. My favorite example is, "I'm stuffed."
American = "The meal you served filled my stomach to fullness"
English = something rather different
;-) A doo run-run-run, a doo run-run
English people - even polite English people - wouldn't often say 'I'm stuffed' to mean 'I'm screwed.'
But they might say 'You're stuffed' or 'We're stuffed' or 'They're stuffed.'
Or they could say 'Well, that's me stuffed.'
Or 'I'm seriously stuffed.'
But without modification in the first person 'I'm stuffed' usually just means 'I'm full.'
Wonder if the American usage has spread through films/books? A doo run-run-run, a doo run-run
Today English is much more about exaggeration - hence 'seriously, 'so', 'totally', etc.
This makes machine translation hard because you don't just have to parse the words, you have to parse that specific kind of formation, and also know something about the class and age of the person speaking.
This is where machine translation goes wrong - a lot of communication is at least as much about role play with canned phrases and constructions as about grammar.
For spoken language you can't make sense of the meaning just from the grammar rules on their own. You need to know the role play context and also have a library of current constructions.
Written language is simpler because it's more formal and structured, but you can still fall over some of the wackier constructions that turn up.
I thought it was normal that one could have fun with language. It wasn't till high school that I found it necessary to restrict the fun a bit. But that 'fun with language' of my childhood remains a major component of my writing today, though I find it harder in Finnish because you can't mistreat it in the same way and still expect to make sense. You can't be me, I'm taken
And what about the English biscuit company who failed to export their main product to the US - Ginger Nuts. You can't be me, I'm taken
