Samsung Metro 350 has quite good battery backup. It comes with 1200 mAh removable battery and on a single charge it can last up to almost almost 4 days.
Samsung Metro 350 do not have too loud speaker but the loudness is quite comfortable.
Samsung Metro 350 has 1000 contact storage capacity.
Yes, Samsung Metro 350 does have Hindi language option.
Yes, Metro 350 does support Gujarati language.