
Normal people singing? Beyond rousing and inspiring there wouldn't be any actual physical effect on people.
A Bard singing? Its confirmed in lore that their songs can boost their companions effectiveness according to the song being sung, be that swifter movement, greater damage or limiting the damage sustained from their foes.
A Bard singing? Its confirmed in lore that their songs can boost their companions effectiveness according to the song being sung, be that swifter movement, greater damage or limiting the damage sustained from their foes.