spontaneously

Raymond chose his poems spontaneously on the day, while I was sitting on the floor surrounded by a few small resonant instruments.

The protests emerged spontaneously in some of Luanda's more populous and poorer neighbourhoods, where some residents lack access to basic sanitation as well as other essential infrastructure.

Later, as he digs into the making and meaning of his movie, he’ll relax and the words will spontaneously flow.

Either the liver ruptured because of a needle or it ruptured spontaneously.

It's still not clear why the outbreak spontaneously ceased and it hasn't resurged over the past decade.