[carom]

>“I did [a noun]” is grammatically correct English object-verb-direct-object sentence structure.

I'm going to need some examples here because I'm filling in nouns to that structure and it does not sound correct. "I did [a] water." Huh?

[stonemetal12]

"I did a runner" British idiom means I ran away without paying. The only problem with "I did a water" is I don't know what "a water" is without context. If person A said "I did a shot" and person B said "I did a water", it would make perfect sense.

[thfuran]

I can't offhand think of a case where that construction is appropriate for a noun that isn't a nominalized verb.

[RandallBrown]

I did a dance.

I did a presentation.

[sorcerer-mar]

So things that people do, of which "ouchies" is not

[RandallBrown]

Why can't you do an ouchie? It sounds weird, but I also know exactly what it means.

[sorcerer-mar]

Feel free to teach your child whatever you’d like, language is totally fungible.

The reason I’d suggest not to is because speaking in this way will, in fact, cause people to think less highly of you.

It’s not a matter of principle and “formal correctness” is pretty meaningless in human language, but “don’t speak in a way that a substantial number of people regard as incorrect” is a meaningful goal!

[watwut]

I would argue that people who think less of a three or five years old because the kid said "I did an ouchie" are simultaneously irrelevant and frankly dumb themselves. Kids life wont be affected at all.

Your claim is really based on fairly absurd notion that a sentence normally used in relation to the kids will somehow set the kid apart from their peers ... who listen to the exact same sentences. As in, the problem of kids speech somehow damaging kids long term is literally non existent in real world.

Miniscule percentage of parents takes offense on it and nobody else cares.

[sorcerer-mar]

Obviously we’re talking about kids acquiring language, I.e. should the response be to nudge them toward more accepted language as they develop, or make up silly overintellectualized arguments like “hmm, well I can understand what they mean! [insightful face emoji]”

“Aww cute!” responses to incorrect language is how kids develop speech impediments.

[quesera]

I did art. I did postgrad. I did work(n). I did dishes. I did Paris. I did the walls, but hired someone who did the roof.

Not idiomatic for all nouns, esp those for which there's a more applicable verb.