Avoid the plural forms

English for Today by Ganiu Abisoye Bamgbose (Dr GAB)

I need to get some stuffs later today (nonstandard).
I need to get some stuff later today (standard).

He uses slangs always (nonstandard).
He uses slang always (standard).
He uses slangy expressions always (standard).

We need to train our staffs (nonstandard).
We need to train our staff (standard).
GAB