Learn Turkish: "Bu hangi dil?" diye sordu. - She asked, "Which language is this?"

In Turkish, diye acts as a linking word to connect a direct quote to the main verb. It comes from the verb demek (to say) and translates literally to "saying." So, the structure is essentially: "[Quote]" saying, she asked. You will see diye used this way before verbs like sormak (to ask), düşünmek (to think), or bağırmak (to shout).

Why isn't there a verb meaning "is" at the end of the quote Bu hangi dil?

In everyday Turkish, simple present-tense sentences often do not need a visible "to be" verb. Bu hangi dil? literally means "This which language?" The "is" is naturally understood. Adding the formal "is" suffix to make it Bu hangi dildir? would sound a bit too stiff for a simple conversational question.

Does the punctuation always stay inside the quotation marks before diye?

Yes! The original punctuation of the spoken sentence, like the question mark here, stays inside the quotation marks. Then you just continue with diye and the main verb, ending the overall sentence with a standard period.

Could I translate "Which language is this?" as Hangi dil bu? instead?