Yáʼátʼééh shikʼis! I am reporting the sentences that reject the plural (or singular) translation in the object. Both singular and plural nouns (an / the apple / apples) are valid here. Some verbs can be different, for example when describing the color. The sentence "This apple is red." will use the noun "bilasáana" with a singular verb, and the sentence "These (three or more) apples are red." will use a plural verb with the same noun. Remember that the duoplural form is the same as the singular in this case, in the third person. So, "My apple and your tomato (they two) are red." will use the same singular form in Navajo.
I hope it helps. :)
It definitely does, especially as the use of the term "duoplural" had me looking up this interesting situation in Navajo. So, is there no duoplural form in the object position? Does the stative verb "to be red" require the singular subject even when the verb is plural for some reason? The little Navajo program here does, at least, introduce some interesting issues.
For example, dootłʼizh is the third person (singular / duoplural) verb conjugation used for the colors "blue" / "green" / "turquoise", while dadootłʼizh is the plural:
he/she/it is turquoise, green, blue
Łóóʼ dootłʼizh ― The (one or two) fish is/are blue.
Łóóʼ dadootłʼizh ― The (three or more) fish are blue.
It is also important to notice that the first and second person verb conjugations have three different forms, each one, for the singular, duoplural and plural. I think this is still a special case for the color description, where the verb presents some interesting compositions using the perfective stem -tłʼizh.
di- (“color”) + -oo- (yi-perfective 3rd person subject prefix) + -d- (classifier) + -tłʼizh (neuter perfective stem of root -TŁʼIIZH, “to be blue, green”).
It's very inconsistent, along with the articles for the nouns. Duo should accept both 'eats' and 'is eating', and any article, afaik. I guess for now, just remember that Navajo doesn't make these distinctions and figure out whatever answer Duolingo wants for the particular example.