"He is cold today."
Translation:Anuanu ʻo ia i kēia lā.
I guess this is a question for a lot of example sentences here, but it stood out for this one in particular to me for some reason. Why isn't it gramatically correct to say "He anuanu 'o ia i kēia lā"? When do we use "he" and when do we not? I feel like half the time I use it, it gets marked as wrong.
"He" is an indefinite noun marker. When you start a sentence with "He" it means that the next thing is an indefinite noun. I'm not even sure what "anuanu" as an indefinite noun would mean, but your suggestion comes out as something like, "She is a cold today."
To explain what's going on in the Hawaiian here, I think it will help for you to understand something about English copulas. A copula is a structure that relates one thing as being the same as or described by another thing. In English, to create a copula we connect two nouns with the verb "to be": "My father is a teacher." This uses two noun phrases "My father" and "a teacher" and equates them with the verb "to be": My father = a teacher.
Hawaiian has a copular construction, too, but it doesn't use a copular verb to connect two nouns - there is no verb that means "to be". Instead, Hawaiian just places the two nouns next two each other and arranges them so the sentence begins with the determiner He, or if neither of the terms is already using the determiner He, then arrange them so that the determiner 'O is first, or if neither term uses either the determiner He or the determiner 'O then place an added 'O at the beginning.
"He kumu ko'u makua kāne." (He kumu = Ko'u makua kāne. "My father = a teacher.")
'O kāu kumu ko'u makua kāne. (kāu kumu = ko'u makua kāne. "My father = your teacher.")
English also uses the copular structure with the copular verb "to be" in order to create adjectival statements. "My father is kind." Here we are connecting a noun to an adjective. In English we think of it as being the same kind of construction, but it is important to note that since this is connecting a noun to an adjective, it's a slightly different structure from when we connect two nouns. We can also use the adjective to directly describe the noun: "My kind father". Here we are not making a statement about the noun and we don't use the copular construction. Instead we are simply modifying the noun so that it can be used in a larger statement: "My kind father is a teacher."
Hawaiian has words that are very much like adjectives and can be used in that same way to modify nouns, but follow the noun they are modifying: "ko'u makua kāne 'olu'olu" ("My kind father"). We can then use this noun phrase in a statement:
He kumu ko'u makua kāne 'olu'olu. (He kumu = ko'u makua kāne 'olu'olu. "My kind father = a teacher.")
But when we want to create an adjectival statement about some noun, Hawaiian uses a slightly different structure. Again, there is no copular verb like "to be", so Hawaiian just places the adjective at the front without any determiner: 'Olu'olu ko'u makua kāne. ("My father is kind.") In a way this is very similar to the Hawaiian copular structure with the exception that no determiner is used. That very much resembles when a regular verb is used - you just place it at the beginning of the sentence and put the one doing (or being) that verb right after. Because of this, this structure is often described as using the adjective as a verb, in which case we often say that "to be" is included within that adjectival verb. 'Olu'olu can be defined as "to be kind" and no additional verb or marker indicating "to be" is needed.
So now we can look at the sentence from this exercise which is using an adjective/adjectival verb to make a statement about someone. Because it is not a noun we do not give it any sort of marker and just put it at the beginning of the sentence:
Anuanu 'o ia. ("He/She is cold.")