Deniz suyu tuzlu.

to be

Breakdown of Deniz suyu tuzlu.

• tuzlu: salty
• deniz suyu: the sea water

Questions & Answers about Deniz suyu tuzlu.

Why is there no to be verb like is in Deniz suyu tuzlu?

In Turkish, the present-tense copula ("to be") is usually omitted in simple nominal sentences.
So Deniz suyu tuzlu literally reads "sea water salty" but is understood as "sea water is salty."
If you want to be more formal or explicit, you can add the suffix -dur: Deniz suyu tuzludur ("Sea water is salty").

What does the suffix -lu in tuzlu mean?

The suffix -lu (with vowel harmony: -lı/-li/-lu/-lü) attaches to nouns to form adjectives meaning "with" or "having."
For example:
• tuz (salt) + -lu → tuzlu ("salty," literally "having salt")
• şeker (sugar) + -li → şekerli ("sweet," "having sugar")

Why is it suyu instead of just su?

Here Deniz suyu is a noun-noun compound meaning "water of the sea." In Turkish compounds like this:

1. The second noun takes the 3rd person possessive suffix -(s)ı/-(s)i/-(s)u/-(s)ü (here su → suyu).
2. The first noun remains in its bare form (deniz).
   So deniz suyu = "its (the sea’s) water."