"tá dath X ar Y" is just one of many Irish idioms.
(By the way: It is a good one because usually things (and people) aren't colored to the core, only the surface is yellow, or green, or black. The interior can differ.)

Fronting does not permit any word being fronted: Phrases of two or more words which are felt as a unit aren't divided, e.g. noun + adjective, preposition + noun, ag + verbal noun, etc.
The noun phrase "dath buí" is such a unit (noun + adjective), so the whole phrase must be fronted.

Your proposal:
"Yellow isn't the colour of the balls" = Ní buí atá dath na liathróidí. (I wonder if a native speaker would say so.)
The analogue normal (unfronted) sentence is:
Níl dath na liathróidí buí. = "The color of the balls is not yellow".

WAIT I lied. This one no longer seems right to me.

Why isn't it:
Níl aon duine de na páistí ina shuí
???
Isn't "duine" masculine? Or was that just an assumption on my part....

Also, for whatever reason "Ní oireann." sounded like it needed an "h" to me. But h is for when it wouldn't be lenited, right? Like for feminine possession instead of masculine? Sorry to throw totally new questions in here

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ЯГОН ТОҶИК НЕСТ ИНҶО???

On the first one, it's not referring to a particular kid, but to all of them as a group, so it uses the "their" form of a. At least that's how I'm interpreting it, though it could be English interfering.

As for the second, you probably think of that because ní prefixes an h before pronouns

I think it's English 'interference' as you said suggesting to me that it's wrong because in English we would say "Not one of the children is sitting." or "None of the children is sitting." both with singular verbs. Like in English, the subject "aon cheann / not one / none" is obviously singular so that's where I'm confused.



That's totally it. Awesome. Thanks.

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ЯГОН ТОҶИК НЕСТ ИНҶО???

I think you'd say "níl aon duine do na páistí ina shuí", and you would also say "bhí achan pháiste ina shuí", even though "achan pháiste" technically refers to several children (just like "every child" in English).



ní doesn't prefix h to verbs that start with a vowel.

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