I find that when I perform my prayers in Arabic it feels like a chore and I remain unfocused and hurry to finish them, whereas when I recite them in English translation the effects are the opposite. Can I pray in English or in both Arabic and English?
as salam alaikum
a translation of the Qur'an is not the Qur'an therefore it is necessary to recite it in the Arabic language during the salat. Other intentional extra-words would invalidate the prayer. It is advisable to try as much as possible to take familiarity with the Qur'an in order to always feel in harmony with it.
With prayers for your success.