Linguistic ability is good but a lack of it wont hold you back.
It will at army.ca

I think we need to stop considering commissionaires as some of defense against anything. Or anyone who isn'r armed for that matter. Most bases's I've seen have zero security. You could drive a big ol van pretty much anywhere you want on base and park it next to some expensive equipment or lots of people -if you know what I mean.
On the flip side of the coin, Petawawa for example, would riot if the CF started stopping everyone at the 2 gates in and out to check ID. Getting on and off base at peak time is insane enough already.
Heightened security means longer wait times, more frustrations, longer commutes.
Commissionaires seem to have some training issues. I showed up at my armory on a holiday in civies to check email. The guy let me in and opened up the company office for me. I (politely) suggested he check my military id, write my info down and check to see if I was on the list of people authorized keys.
He was pretty thankful, he told me he had zero 'hand over' or info passed on and when he started to ask questions he said he was told not to worry about it, it's a holiday and people probably wouldn't show up. Not exaggerating.
As for weapons training.
Commissionaires should not teach it, period.
All soldiers should be highly trained and skilled, but that doesn't always happen.
On our FTX before deploying a navy clerk asked me how to use the C7
during a patrol with blank ammo, enemy force in the village we were approaching.
She hadn't touched a C7 in 7 years.
My platoon left the wire every day overseas, half of us didn't have zeroed weapons for the first 2 months.