Money and cards
The Malaysian ringgit, written RM. Cards are taken without question in malls, hotels and chain restaurants, but hawker stalls, wet markets and the older kopitiams are cash or local QR only. Carry small notes for food. The Touch 'n Go eWallet that locals pay with generally needs a Malaysian phone number and bank account, so plan on the physical Touch 'n Go card for transport and cash for food rather than expecting to go cashless.
Tipping
Not expected, and not a part of the culture. Mid-range and upper restaurants normally add a service charge and government tax to the bill already, so read the bottom of the bill before you add anything on top. Nothing is expected at hawker stalls, in taxis or at food courts. Rounding up a Grab fare or leaving the coins from your change is a generous gesture rather than a baseline.
Power and plugs
Type G, the large rectangular three-pin British plug, is the Malaysian standard, though Type C and Type M sockets turn up in older buildings. The supply is 230 volts, which you will also see quoted as 240, at 50 hertz. Canadian plugs do not physically fit, so you need an adapter. Phone and laptop chargers are dual voltage and will be fine on it; a Canadian hair dryer, curling iron or travel kettle rated only for 120 volts will burn out, so check the label for a 100 to 240 volt range before plugging anything in.
Tap water
Treated to a drinkable standard at the plant, but the ageing distribution pipes and the rooftop storage tanks on most buildings are the weak point, which is why Malaysian households boil or filter it. Do the same: drink bottled or boiled. Canada's official advice for Malaysia is the standard boil it, cook it, peel it or leave it. Ice in established restaurants, hawker centres and malls is commercially produced and generally fine.
Language
Bahasa Malaysia is the national language, but English is very widely spoken in Kuala Lumpur and appears on transit signage, menus, hospital notices and government forms. You will not need a translation app. Malaysian English moves fast and drops articles, so an older relative may need people to slow down, but this is a genuinely low-friction city for anyone who only speaks English.
Safety
Canada rates Malaysia as take normal security precautions, with a higher regional advisory for the east coast of Sabah that does not affect Kuala Lumpur. The advisory flags pickpocketing, purse snatching and snatch-and-grab incidents as the prevalent petty crime, and in KL that most often means a bag taken by a thief on a passing motorcycle, with people pulled over and injured rather than simply robbed. Walk with your bag on the side away from the road and the strap across your body, not hanging off one shoulder. Canada's advisory also notes that credit card magnetic strips have been duplicated even in international hotels, so tap rather than swipe, cover the keypad and keep the card in your sight.