おい oi、おっさん ossan！何(なに) naniやってん yattenだ daよ yo！ Hey, old man! What the hell are you doing!? Literal Hey, old-man! What doing [progressive-てんだよ]! おい is a blunt masculine attention-getter. おっさん 'old man / middle-aged guy' is a casual/slightly rude term. やってんだよ is the contracted form of やっているんだよ — explanatory のだ + assertive よ. A short, aggressive confrontational outburst. confrontation~のだ / ~のです (explanatory)~てる (contraction of ~ている)
おい oi、おっさん ossan！何(なに) naniやってん yattenだ daよ yo！ Hey, old man! What the hell are you doing!? Literal Hey, old-man! What doing [progressive-てんだよ]! おい is a blunt masculine attention-getter. おっさん 'old man / middle-aged guy' is a casual/slightly rude term. やってんだよ is the contracted form of やっているんだよ — explanatory のだ + assertive よ. A short, aggressive confrontational outburst. confrontation~のだ / ~のです (explanatory)~てる (contraction of ~ている)