"They are drinking the soup with salt."
Translation:Çorbayı tuzlu içiyorlar.
Yes, one is an adjective (sütlü çorbayı) meaning "soup with (made with) milk." The other is an adverb describing how you eat it. (çorbayı sütlü..." It can mean that you drink your soup after you add milk or you drink it with milk on the side. This sentence is vague in the English :)