Breakdown of Vahşi bir kabile şehri istila etmiş olsa gerek.
bir
a / an
şehir
city
olmak
to be
gerek
necessary
Questions & Answers about Vahşi bir kabile şehri istila etmiş olsa gerek.
How does the grammar in etmiş olsa gerek work to mean "must have invaded"?
This sentence uses the target structure for past logical deductions: -mIş olsa gerek. The verb istila etmek (to invade) is put into the past form istila etmiş (has invaded), and olsa gerek adds the strong deduction (literally "it must be that..."). Together, they create the meaning "must have invaded."
Why is şehir written as şehri here?
It has the accusative suffix -i because "the city" is the specific direct object of the invasion. Şehir (city) is one of the Turkish words that drop their narrow vowel in the second syllable when a suffix starting with a vowel is added. Therefore, it becomes şehri instead of şehiri.
Why is the word order vahşi bir kabile and not bir vahşi kabile?
In Turkish, when a noun is modified by both a descriptive adjective and the indefinite article bir (a/an), the standard and most natural word order is Adjective + bir + Noun.
Could we say istila etmişler olsa gerek since a tribe consists of many people?
You generally shouldn't. Although kabile (tribe) refers to a group of people, it is a grammatically singular collective noun in Turkish. Unless you are talking about multiple tribes (kabileler), the verb remains in the singular third-person form.