"동물이 메시지를 씁니다."
Translation:The animal writes a message.
To be honest, the hardest part for me is that Duo keeps changing what level of formality is being used and I think that's a bit of what they are talking about. I did read a bit more of the comments talking about how there are two different words being used as well, but apparently they both have different technical definitions. Both of these, though, are making me want to go back to more of a self-taught style of learning Korean... Duo is making things a bit too complicated.. :(
Please read the comments, this was answered higher up. “쓰다 is the verb for "to use" but it is usually what you use for "to write" per CooperReid4. So, in English if someone were using a message, I would assume that person was reading it, but Korean is a different language and “uses a message” apparently not only means “writes a message” but it is more common to use that than to use the actual verb “writes”.
적습니다 refers to writing something, usually by hand. 씁니다 (note the difference between ㅆ and ㅅ) usually means to write something, but can also mean to use something.
In English, for example, we can write, scrawl, jot, inscribe... sometimes there are multiple, slightly different words for an action.
Serious Question: How do I know when to use 쓰다 and when to use 적다? Are they interchangeable? [Yes, I know 쓰다 can mean "to write; to use; to be bitter; to wear a hat or sunglasses; to administer medicine.] Previous sentences about writing used 적다. So I wrote that word, and the program marked it wrong. Can they both be correct? Some Moderator, please read and answer this question! Thanks!
Message is the direct object of the verb, but "to be bitter" taken as one verb is not transitive (it doesn't have a direct object). Also, Animal is the subject. Animal would need the possessive particle and message would need the subject particle for that to work.
In English, animals covers all of those and never just mammals. What about marsupials, reptiles and amphibians? Sometimes people do say animals when talking about land animals as opposed to animals of the water and sky and insects are often separated out. Even people can be considered animals, though are often considered to be separate.