Simplify the following text for a Grade 8 native English-speaking person.
Original: Alternative country ( sometimes alt-country , insurgent country , or Americana ) is a loosely defined sub-genre of country music , which includes acts that differ significantly in style from mainstream or pop country music .
Simplified: Alternative country ( sometimes called alt-country , or Americana ) is a type of country music . It has singers or bands that sound very different mainstream or pop country music .