The first people of the Northern Mariana Islands navigated to the islands at some period between 4000 BCE to 2000 BCE from South-East Asia. They became known as the Chamorros, and spoke an Austronesian language called Chamorro. The ancient Chamorro left a number of megalithic ruins, including Latte stone. The Refaluwasch, or Carolinian, people came to the Marianas in the 1800s from the Caroline Islands. Micronesian colonists gradually settled the Marshall Islands during the 2nd millennium BCE, with inter-island navigation made possible using traditional stick charts.