Traditional music is often called folk music or even (1)_ world music. It is described in different ways, as music off (2)_ lower classes, or music by (3)_ unknown composers, or music which usually doesn’t have (4)_ written form. Folk music is passed on orally, in (5)_ other words, it’s not written down. (6)_ songs of (7)_ particular type of folk music are learnt and played by members (8)_ community and (9)_ next generation of musicians learns them by listening and watching. In this way, (10)_ songs are kept alive. (11)_ original song may go through many changes over (12)_ years. Perhaps (13)_ best description of traditional music is ‘folk music is what (14)_ people sing’.

Как я поняла, тут нужно вставить артикли?

Traditional music is often called folk music or even "the" world music. It is described in different ways, as music of lower classes, or music by unknown composers, or music which usually does not have a written form. Folk music is passed on orally, in other words, it is not written down. Songs of "a" particular type of folk music are learnt and played by members of the community and the next generation of musicians learns them by listening and watching. In this way, "the" songs are kept alive. The original song may go through many changes over years. Perhaps, "the" best description of traditional music is: 'folk music is what people sing'.

Вроде так,  " - знак артикля, везде ставить не буду, поймёшь