The English is not exactly politically correct, and today one would use "indigenous people" rather than "natives", and "unconsciously" rather than "insensibly".
That might explain the origin (on the assumption that the Enc. Brit. is correct), but not the meaning:
no doubt someone in Sabah will know.
I look forward to reading the rest of the answers.
Rev David Hubbard, London, England
Before North Borneo was named Sabah at independence, there was a newspaper already known as Sabah Times, set up by Chong Pak Nam and the Daily Express founder Yeh Pao Tse who engaged Donald Stephens as its editor.
This is not the absolute correct answer. Just my 2 c.
William Wang, Sabah, Malaysia