First of All we hace to understand about Details of Prayers.

Prayer in Arabic cements the Islamic brotherhood and emphasizes the universal character of Islam. Islam has come for the entire Human race.

The Prophet May Peace be Upon Him said: (Pray like you see me pray)

And He Prayed in Arabic, so we follow Him and Pray in Arabic. 

Most importantly
Supplicating in other than the Arabic language for a person who does not know Arabic is permissible, whether it be in the prayer or outside of the prayer. 

Allah Says,
لَا يُكَلِّفُ اللَّهُ نَفْسًا إِلَّا وُسْعَهَا (286)
(Interpretation of the meaning 👇)
Allaah burdens not a person beyond his scope.
 (Al-Baqarah 2:286)

What we Repeat in our Prayers is the the same thing.

Like 
Reciting Surah Fatiha, Takbeer, Tasbeeh. 

And learning Surah Fatiha brings great benefit in our lives. 

We recite Quranic Surahs in our prayers 

There must've been a reason for sending down Quran in Arabic

of course! The first step of teaching the path of Islam to the whole world is to teach it to the very people of Makkah. And for that, it needed to be in Arabic.

Allah Says,
إِنَّا أَنزَلْنَاهُ قُرْآنًا عَرَبِيًّا لَّعَلَّكُمْ تَعْقِلُونَ(2)
(Interpretation of the meaning👇)
Indeed We have sent it down as an Arabic Qur'an so that you may apply reason.
Chapter 12 Verse 2

فَإِنَّمَا يَسَّرْنَاهُ بِلِسَانِك لَعَلَّهُمْ يَتَذَكَّرُونَ "
(Interpretation of the meaning 👇)
Thus We have revealed this [Qur'an] to you in your own tongue so that they may take heed.
Chapter 44 Verse 58

People would have doubted the whole system.

If the Qur'an had been revealed in the language of the non-Arabs, they would have said, because of their stubbornness:

Allah Says,
وَلَوْ جَعَلْنَاهُ قُرْآنًا أَعْجَمِيًّا لَقَالُوا لَوْلَا فُصِّلَتْ آيَاتُهُ أَأَعْجَمِيٌّ وَعَرَبِيٌّ قُلْ هُوَ لِلَّذِينَ آمَنُوا هُدًى وَشِفَاءٌ وَالَّذِينَ لَا يُؤْمِنُونَ فِي آذَانِهِمْ وَقْرٌ وَهُوَ عَلَيْهِمْ عَمًى أُولَئِكَ يُنَادَوْنَ مِنْ مَكَانٍ بَعِيدٍ(44)
(Interpretation of the meaning 👇)
And if We had sent this as a Quran in a foreign language other than Arabic, they would have said: "Why are not its Verses explained in detail (in our language)? What! (A Book) not in Arabic and (the Messenger) an Arab?" 
Chapter 41 Verse 44

Moreover, the Qur’aan is a miracle in its wording and its meaning; if it is changed, this is no longer the case, and it is no longer Qur’aan but an interpretation 

Conclusion: 
Keep in Mind!

1) Islam Always Encourages us for unity even in matters of Worship.
2) It's continuity with the arabic language helped maintain the Purity of The language of the Qur'an. 
3) Qur'anic Arabic is a challenge even for the Arab World.
4) Arabic Was the prophet's Language .
5) We hear and we obey as a Muslim.
6) Whatever Allaah likes for us is always better.

As Allah says
ۚ هُوَ اجْتَبَاكُمْ وَمَا جَعَلَ عَلَيْكُمْ فِي الدِّينِ مِنْ حَرَجٍ ۚ ﴿٧٨﴾
(Interpretation of the meaning 👇)
He has chosen you andk has no aplaced upon you in the religion any difficulty. 
Chapter 22 Verse 78

May Allah guide us to what is good in this life and the hereafter.