jomsayin

Abbreviation of 'Do you know what it is that I am saying'
Used in gangs.

just smoked a 10 bag mate, jomsayin

Deh

Abbreviation of 'Yeah?'

Used when someone is chatting so much dogshit and you can't be bothered to form an argument against them because you know your argument would get lost in the amount of shit they're producing.
Pronounced 'D-E'

Someone: 'Oh mate, last night I fingered 8 birds and shagged 3'
Me: DEH?
Someone: ....

raimei

Stands for 'are you alright mate'
Normally used by smokers of marijuana as they lack energy to complete full sentences.

Was founded in North Wales.

Me: Raimei?
Someone: Ye mei.
Me: Ok mei.

Someone: *Hits blunt* Raimei
Me: *Hits blunt* Ye mei.