In ancient times, when the island of Borneo was still only sparsely inhabited, those who dwelled there lived in fear of many kinds of demons, dwarfs and spirits. These beings might either look after men or else punish them with death if they broke taboos.
As spirits (antu) were everywhere, men had to be very careful in what they said and did. They could not speak arrogantly when they fished the river or hunted the forests. If they did so, boasting that they could easily obtained fish or game, their efforts would come to nothing.
Then, this is where, we have ‘Jaku Kelaung’ (indirect), which the spirit couldn’t understand.
1. Aku deka nginti pagila (Im going to fishing tomorrow) – Which is wrong (Direct, the Spirits understand them)
2. Aku deka “Bemain Ai” (Nginti/Fishing) nganti hari “Bekalih Batang” (Pagila/Tomorrow)
Similarly, an individual was strictly forbidden to mock other living things; if he did so, the spirit would destroy him with kudi, a violent supernatural storm in which a culprit and all his belongings were turned to stone (batu kudi).
Houses and human beings believed to have been petrified in the past can still be seen in many places in Sarawak.