both should be accepted.
Polish (like many languages) has two words for "you", or more if you count formal ways of adressng people.
You(thou)- margotgm and nobody else = ty
you(you all)- margotgm and someone else= wy
as Polish verbs change depending on subject. ty piszesz is different than wy piszecie, but both are translated to you write, even though they mean two different things.
"List" is both the accusative singular and nominative singular form of the word "letter" in English
That does not seem correct. It suggests writing a Polish special character: Ł, Ą, Ń...
If list means letter, what is the Polish word for list? Example, shopping list
Lista -> (shopping) list,
List -> letter,
Litera -> letter, like A, Ą, B ...
Liść -> leave (those on threes),
In Polish, list is derived from liść.
What is list here? Duolingo dosent even translate the sentance after you fill in the word... just says you got it correct
list is a written message that you send to someone, usually by post
litera is a symbol that is used in written language and that represents a sound in that language
in this sentence list is in accusative form ( after pisac), but accusative and nominative look the same.
If English word has more meanings that translate differently I think http://dictionary.cambridge.org/dictionary/english-polish/letter is a good place to check.
"You're writing a letter in polish language"
This isn't accepted. Should it be?
Well... that adds the word "języku" (and changes the structure to "w języku polskim"), plus I really think that most natives would just say "in Polish"... I'd say that's a bit too far.
It sounds a "little" tuncated but "you write a polish letter" is really that bad?