Questions & Answers about To jest list do niej.
Why do we use niej here instead of jej for "her"?
Both niej and jej mean "her" in this case, but Polish adds an n- to the beginning of third-person pronouns when they come directly after a preposition. Since it follows the preposition do (to), jej becomes niej.
What case does the preposition do require in this sentence?
The preposition do always requires the Genitive case. That is why we use the Genitive form of the pronoun ona (she), which is jej (changed to niej because of the preposition).
Could I drop the word jest and just say To list do niej?
Yes! In Polish, it is very common to leave out the verb jest (is) in simple sentences that start with To (this/it). Saying To list do niej is perfectly correct and natural.
Why doesn't the word list have a special case ending here?
The word list (letter) is in the Nominative case (the basic dictionary form) because it tells us what the subject of the sentence is. It does not need a special ending in a basic To jest... (This is...) sentence.