"Drink water with salt."
Translation:Tuzlu su iç.
The first one implies that the water "contains" salt. The latter implies that they are separate (like how some people lick salt after drinking tequila).
There are two different suffixes here: -lI means "with/containing" and is used with mixtures, -(y)lA is a case and would be "with/accompanying/along with" :)
-(y)la can also be used to mean "and" sometimes.
Is salted water a thing now? I've seen this example too many times with different constructions. I'm all for the funny nonsensical examples (I actually love them and think they are what make Doulingo different and fresh, in addition to keeping one on edge while practicing); however, unless in certain "very specific" situations, this can be a dangerous thing to instil into children's (or adults) brains! Fruit for thought!