20:27
وَٱحْلُلْ عُقْدَةً مِّن لِّسَانِى
wa-uḥ'lul ʿuq'datan min lisānī
Untie my tongue,
"And loose the knot (the defect) from my tongue, (i.e. remove the incorrectness from my speech) [That occurred as a result of a brand of fire which Mûsâ (Moses) put in his mouth when he was an infant]. (Tafsir At-Tabarî).