Dua Before Giving a Speech or Taking a Test

رَبِّ اشْرَحْ لِي صَدْرِي وَيَسِّرْ لِي أَمْرِي وَاحْلُلْ عُقْدَةً مِنْ لِسَانِي يَفْقَهُوا قَوْلِي
Rabbishrah lee sadree wayassir lee amree wahlul 'Uqdatam-mil-li saanee yafqahoo qawlee.'
(O my Lord! Expand for me my chest; ease my task for me; and remove the impediment from my speech; so they may understand what I say.) (Surah Ta-Ha, 20:25-28)