First of all, I couldn't understand and looked at his face.
firstly, in the first place, first of all
Inherited from Ottoman Turkish اولا (evvela, “firstly, in the first place”), from Arabic أَوَّلًا (ʔawwalan).
Ćwicz mówienie i zapamiętywanie " evvela " i wielu innych słów i zdań z turecki .