▁time , ▁usually ▁several ▁gener ations . ▁ ▁As ▁a ▁side - effect , ▁the ▁following ▁characteristics ▁are ▁sometimes ▁present : ▁ ▁There ▁is ▁no ▁copy right ▁on ▁the ▁songs . ▁H undred s ▁of ▁folk ▁songs ▁from ▁the ▁ 1 9 th ▁century ▁have ▁known ▁authors ▁but ▁have ▁continued ▁in ▁or al ▁tradition ▁to ▁the ▁point ▁where ▁they ▁are ▁considered ▁traditional ▁for ▁purposes ▁of ▁music ▁publishing . ▁This ▁has ▁become ▁much ▁less ▁frequent ▁since ▁the ▁ 1 9 4 0 s . ▁Today , ▁almost ▁every ▁folk ▁song ▁that ▁is ▁recorded ▁is ▁cred ited ▁with ▁an ▁arr anger . ▁ ▁F usion ▁of ▁cult ures : ▁Because ▁cult ures ▁interact ▁and ▁change ▁over ▁time , ▁traditional ▁songs ▁evol ving ▁over ▁time ▁may ▁incorpor ate ▁and ▁reflect ▁influ ences ▁from ▁dispar ate ▁cult ures . ▁The ▁relevant ▁factors ▁may ▁include ▁instrument ation , ▁tun ings , ▁vo ic ings , ▁phr asing , ▁subject ▁matter , ▁and ▁even ▁production ▁methods . ▁ ▁Term in ology ▁ ▁T une ▁▁ ▁In ▁folk ▁music , ▁a ▁t une ▁is ▁a ▁short ▁instrument al ▁piece , ▁a ▁mel ody , ▁often ▁with ▁repeating ▁sections , ▁and ▁usually ▁played ▁a ▁number ▁of ▁times . ▁A ▁collection ▁of ▁t unes ▁with ▁struct ural ▁similar ities ▁is ▁known ▁as ▁a ▁t une - family . ▁America ' s ▁Musical ▁Land s cape ▁says ▁" the ▁most ▁common ▁form ▁for ▁t unes ▁in ▁folk ▁music ▁is ▁A AB B , ▁also ▁known ▁as ▁binary ▁form ". ▁ ▁In ▁some ▁trad