Meter/metre is one of those differences between British and American usage, like center/centre, honor/honour, etc. There are other differences, from the placement of periods to the pluralization of collective nouns (the company is/are) which are specific to one dialect or the other. They're generally fairly consistent in their native dialect (though the plural bit has been creeping into American English for some reason) and I just accept them as one of the peculiarities of their native tongue, so long as someone manages to keep them consistent. In a sense, my head shifts gears to whichever version I'm reading, and the other one looks funny even if it's the one I'm used to seeing.
Verbing nouns has happened as long as there has been an English. Look at basic words like walk, swim, drink, etc. Are they nouns or verbs? Yes. I'm not certain, but I believe Germanic languages in general are inclined to do that. Romance languages, on the other hand, are much less so. Words stick properly to their part of speech, and have endings to prove it. Perfectly innocent words are turned into modifiers when needed. English also throws away articles in a way only Slavic speakers can appreciate. In Boston subway cars, there is a sign which says, in English, "passenger emergency intercom in rear of train"; in Spanish, it says "system of intercommunication for passengers in case of emergency is situated in the rear of the train." They both
mean the same thing, but English implies the "is situated", leaves out "the" several times, adjectivates "for passengers" and "in case of emergency", and uses a neologism for "system of intercommunication." This is all very well and good for an experienced English speaker, but newbies (and computers) get headaches trying to sort that out. That's just something English does (along with mugging other languages in dark allies and rifling their pockets for spare vocabulary).
The last time someone tried to inflict another language's rules on English, we got the "rules" regarding split infinitives, the word "and", and sentence-ending prepositions, courtesy of Latin-infatuated pedants. They tried to stick the rules for Latin onto English because Latin was the "ideal" language and ignored usage going back to the foundations of English. Yes, you really
can write "to boldly go", begin a sentence with "and" (but if you do that too much, you'll look like the King James Bible), and put a preposition on the end of a sentence. English always has. Latin can't or shouldn't. But that's Latin, and applying Latin rules to English makes no more sense than applying English rules to Latin, despite the best efforts of 18th-century pedants.
While there are a few whose origins are lost in history ("kick the bucket", for instance) most idioms have a clear and obvious meaning
if used correctly.
Pouring (what?) over papers is ridiculous, but
poring makes perfect sense when you know that "to pore" is "to study". Except, of course, that people taught to pronounce words and then understand the meaning of the sound, rather than to understand the word itself, and who have never seen "pore" in that usage, just use the word "pour" instead (it sounds the same, after all, and they've been taught that's all that matters) and just say "it's an idiom" when asked what it actually means.
If you think of "its"/"it's" as "the letters that make the sound 'itz'" then you'll never know which one to use. But if you realize that "it's" is short for "it is" and substitute as needed to check, and know that "its" is just like "his", you'll always know which one to use. Except, of course, that idiots have taken to writing "her's", "our's", etc., and I expect to see "hi's" any moment. Not only has using apostrophes to make plurals become common, but now they're being used to precede T (yes, "wen't") and before S in words that simply end in S. But, y'know, "English is a living language", right? So "hi's" should be an acceptable alternative to "his" and "wan't" should be a perfectly valid way to write "want", shouldn't it? (I'm inclined to blame fantasy authors who think their characters' stupid names are less stupid if they throw in random apostrophes, but that's just me).
I strongly recommend
this website for checking words.
This is why people should
know their language. Picking a word that sounds kind of like the one they mean is proof that they don't. Words are a writer's tools. I would no more want to read a book by a writer who didn't know how to use his or her tools than I would want to have my car repaired by a mechanic equally unfamiliar with the tools of the trade.