In English, objects are used in plural form when you use them in a sentence talking about a general activity. For example, you eat apples, you read books, you watch films etc. It is wrong to say you eat apple, you read book, you watch film. That is the reason why newspapers is in plural in the sentence above.
"Yersiniz" means "you eat" and "okursunuz" means "you read". I don't exactly understand your question, are you asking about the vowel harmony?