"My grandfather is a nice teacher."
Translation:He kumu ʻoluʻolu koʻu tūtū kāne.
He kumu oluolu kou tutu kane without okina and kahako should be accepted in my opinion.
While writing without the diacritical marks is accepted in the Hawaiian language community, this is a place to learn Hawaiian from the very beginning. Thus, my (ko'u) and your (kou) would be unclear, and pronunciation would be unclear as well. Context would be muddled. At the very least, when newspapers wrote my (ko'u), they kept that one 'okina to prevent the ambiguity with your (kou).
Throw in the second 'okina in " 'olu'olu" and you should get away with it being marked as just a typo ;)
I have noticed that usually adjectives come after the nouns but this one doesn't follow that. Is it because it's a verb or is it just a random exception?