Du'a before public speaking

رَبِّ ٱشۡرَحۡ لِي صَدۡرِي وَيَسِّرۡ لِيٓ أَمۡرِي وَٱحۡلُلۡ عُقۡدَةࣰ مِّن لِّسَانِي يَفۡقَهُواْ قَوۡلِي

Rabbish-rah lee sadree wa yassir lee amree wahlul 'uqdatam mil lisaanee yafqahoo qawlee

My Lord! relieve my mind And ease my task for me And loose a knot from my tongue That they may understand my saying

Qur'an 20:25-28 (Ta-Ha)