Writings and inscriptions (are) difficult to read, so either the experts or a computer (translates) the text.
verbs correctly complete the sentence:
are, translates
With compound subjects joined by or/nor, the verb agrees with the subject nearer to it.
In the first sentence they are talking about “writings and inscriptions” due to the conjunction “y” become those a group the following auxiliary should be plural (are), however in the second sentence they use “either” at beginning, this determiner is singular for this reason the following verb should be in third person (translates). The answer is: are, translates
