Translation:She promised that she would learn the Ukrainian language.
This is not a conditional mood, this is a regular future tense. 'Would' is used in the English translation to make the English sentence grammatical.
In English, you shift tenses in the subordinate clauses in indirect speech:
- She promised: "I will learn Ukrainian." → She promised she would learn Ukrainian.
- Oksana said: "I love you." → Oksana said she loved me.
- Vira said: "I knew this." → Vira said she had known this.
In Ukranian, we don't shift tenses in subordinate clauses:
- Вона обіцяла: «Я буду вчити українську». → Вона обіцяла, що [вона] буде вчити українську.
- Оксана сказала: «Я люблю тебе». → Оксана сказала, що любить мене. (люблю and любить is changed because the person is changed: я люблю́, Оксана любить, but the tense is the same)
- Віра сказала: «Я це знала». → Віра сказала, що вона це знала.
So it's basically just a normal future tense.
If I understand correctly, ‘will’ works if her past promise still refers to the future (even though some time has passed), while ‘would’ means her past promise referred to the then-future at the time of speaking but might not refer to the future anymore. Right?
If my understanding is correct, Ukrainian just doesn’t have this distinction, and both variants should be accepted when translating into English. (If ‘will’ is not accepted, consider using the Report button.)
So, the subjunctive mood is kind of "optional"? It's also valid to say "she promised that she will..."? Also, what happens if one wants to use "is going to learn", should it be "She promised that she was going to learn..."? When put like that, it sounds to me as if she promised that she was going to learn it, but didn't.
To explain to you why so. This is reported speech. Confusing when you learn English-Ukrainian/Russian In English Anna said: "I will learn Ukrainian". = Anna said that she would learn Ukrainian In Ukrainian when making such sentences we do not change the time at the reported part of the sentence Анна сказала: "Я буду вчити Українську". = Анна сказала, що (вона) буде вчити Українську
PS: I am a native Ukrainian/Russian speaker