[icambron]

Oh I notice oddities all the time. Unusual word orders, preposition use, that sort of thing. As an example “I barely have experience of” is perfectly clear but not idiomatic, enough to tag you as likely non-native (compare to “I’ve barely experienced”). The thing about most native English speakers is that we don’t care; we’re just happy everyone else is speaking English. If the cost of every person in the world being able to communicate with me is hearing some very-slightly-off phrasing, that is a great bargain.

(It’s also not always true. While I’m relatively familiar with UK, Irish, Aussie, and NZ English and can often identify them in writing, Indian and Singaporean English still send me for a loop, and I likely mistag them. They have just as strong a claim to “native” as I have, of course, but they sound “foreign” to my ears.)