-[y]le is a different suffix from -li.
-[y]le is the suffix form of "ile" (with). It's 2-way. Gül'le (with Gül) or Tunç'la (with Tunç).
-li is an unrelated suffix. It's 4-way. It is added to a word to indicate that, that substance is used inside something else. For example: Tuzlu çorba = Salty soup. This is a soup that has salt in it. Tuzla çorba would mean Salt and soup side by side.
AHH ÇOK TŞK!! I was confused because tuzlu and sütlü were translated as ''with salt'' and ''with milk'' respectively, and introduced at the same time ''tuz ile'' (instrumental case) might have been as well.
I didn't know they were different, and this clears up a LOT for me. Thank you so much!
I just thought the chart at the beginning of the help and notes was an introduction to the instrumental case, because it said it was showing how to describe ''with'' in both the beginning part AND the instrumental part of the help and notes, so I thought they were the same.
So to clarify, ''sütle'' and ''tuzla'' would be how you could say physically with the milk or salt? Would it be more natural to say süt ile and tuz ile?
I wrote "With Duo or me," which I think is the most neutral way to express this in English, but it got marked wrong. The repetition of "with" seems unnecessary to me. And in English you don't put the first person pronoun first ("With me or Duo" is just less standard than "With Duo or me").