The statement made in verse 2 following immediately is: إِنَّا أَنزَلْنَاهُ قُرْآنًا عَرَبِيًّا لَّعَلَّكُمْ تَعْقِلُونَ (Surely, We have sent it down, an Arabic Qur’ an, so that you may understand).
It is indicative of the situation that those who had asked to be informed of what had happened to Sayyidna ~Yusuf (علیہ السلام) were the Jews of Arabia. So, Allah Ta’ ala revealed this story in their language so that they may ponder over it and attest to the veracity of the Holy Prophet ﷺ and tune their lives in the light of the injunctions and instructions which emerge from this story.
This is the reason why the word: لَعلَّ (la'alla) has been brought in here in the sense of ` so that' because the mindset of these addressees was already known - that they would, despite having the benefit of very clear verses before them, still doubt and delay their acceptance of truth.