Chiedo and chiedi

In lesson 12.1  There is a line:  Se gliela chiedo (If I ask her) and the next line says: Se non gliela chiedi (If you don't ask her).   In these sentences they both refer to a single woman, so I don't see why they are different. When do you use chiedo and when do you use chiedi? 

Hi cedch, 

Thanks for your question!

Let's analyze each sentence to understand their construction better:

1) "Se gliela chiedo" literally means "If (I) ask it to her/him" (in this case we know it's referring to a woman, so it's "to her" instead of "to him"). 

2) "Se non gliela chiedi​" literally means "If (you) do not ask it to her/him" (again, we know it's referring to a woman, so it's "to her" instead of "to him"). 

- "Gliela" is an abbreviated form of "gli" (to her/to him) + "la" (it, a pronoun referring to the thing that you are asking). This term remains the same in both sentences since, in both cases, the subject of the verb is still asking "it" (la) "to her" (gli). 

The main difference between the two sentences is, therefore, the conjugation of the verb "to ask" (chiedere): (io) chiedo is "I ask" while (tu) chiedi is "you ask". 

The other difference is that the first sentence is affirmative while the second one is negative.

Hope this clarifies your doubt, don't hesitate to let me know if I can help you further :)