آسمون اوری گرت دنیانه کرد سرد
This part, and every other Sarlak verse, is in Luri Language, not Persian.
Therefore, the song is in "Persian, Luri" not only "Persian."
Moreover, regarding the comment of the author, it is worth mentioning that "Luri" is more descriptive than Bakhtiyaari in this case.
Yes, Sina Sarlak, as his last name suggests, is indeed Bakhtiyaari. But I highly doubt if the Luri parts are in Bakhtiyaari dialect. Bakhtiyaari dialect of Luri is known for the excessive use of sound /s/. He would have said "'گرتس" for example not "گرت" if it was actually Bakhtiyaari. Therefore, I assume it's actually Minjaai/Luristani (default Luri).
Translation of Bakhtiari Parts :
[1] آسمان را ابر فراگرفت و دنیا سرد شد
[2] من چگونه زیر خاک و سنگ در درون قبر دلخوش باشم؟
[3] اي داد و اي بیداد، من تک و تنها ماندم
[4] مگر قیامت فرا رسد تا بار دیگر کنار یکدیگر بنشینیم
شاعرِ بخشهای فارسی: شهریار