Learn Hardcore Turkish: Antep fıstığı tuzlu.

In Turkish, the present‐tense copula (to be) is normally omitted in sentences with noun or adjective predicates. So Antep fıstığı tuzlu literally reads as Antep pistachio (is) salty without a separate word for is.

Why does tuzlu come after Antep fıstığı, while in English we say “salty pistachio”?

Because tuzlu here is a predicate adjective, not an attributive one. Turkish follows a Subject–Predicate order, so you say
Subject: Antep fıstığı
Predicate adjective: tuzlu
If you actually want “salty pistachio” as an adjective before the noun, you’d write tuzlu Antep fıstığı.

What does the -ı in fıstığı do?

That -ı is the third-person singular possessive suffix. In the compound Antep fıstığı, it marks fıstık (“pistachio”) as “of Antep.” This is a common pattern in place–product compounds (e.g. Bursa kestanesi = “Bursa’s chestnut”).

How is the adjective tuzlu formed from the noun tuz?

Tuz means “salt.” Adding the suffix -lu (one of -lı/-li/-lü, chosen by vowel harmony) turns nouns into adjectives meaning “having or full of X.”
tuz + lu → tuzlu (“salty”)

How would I make the sentence negative?

Add değil (“not”) after the adjective:
Antep fıstığı tuzlu değil.
This means “Antep pistachio is not salty.”

How do I ask a yes/no question with this structure?

Attach the question particle -mu/-mü/-mi/-mu after the adjective (observe vowel harmony):
Antep fıstığı tuzlu mu?
= “Is Antep pistachio salty?”

How do I say “Antep pistachios” in the plural?

Add the plural suffix -lar to fıstık before the possessive marker:
fıstık + -lar + -ı → fıstıkları
So you get
Antep fıstıkları tuzlu.
= “Antep pistachios are salty.”

Why don’t we use an article like a or the before Antep fıstığı?

Turkish doesn’t have a definite article (the), and the indefinite article (a/an) is expressed with bir if needed. Here, no article is used:
Antep fıstığı tuzlu.
If you wanted to say “A pistachio from Antep is salty,” you’d say
Bir Antep fıstığı tuzlu.