I previously discussed (here) the fact that Bruneians tend to include themselves when counting their siblings; so if I have one brother and two sisters, then speakers of English in Brunei would tend to say that I have four siblings.
My UBD colleague, James McLellan, has told me that this comes from Malay, where the following sentence:
Saya ada empat orang adik-beradik
I have four (people) brothers-and sisters
would mean 'I am one of four children', not 'I have four brothers and sisters'; and various FASS collaeagues, including our Dean, Noor Azam, yesterday confirmed this usage.