It's not a line that's crossed. It's just the standard in Canada.

In Britain, aeroplanes are made of aluminium and they have tyres. The Ministry of Defence sends them out on manoeuvres in theatres of combat, where the pilots have generally excelled due to regular practice.

In America, airplanes are made of aluminum and they have tires. The Department of Defense sends them out on maneuvers in theaters of combat, where the pilots have generally exceled due to regular practise.

In Canada, airplanes are made of aluminum and they have tires. The Department of National Defence sends them out on manoeuvres in theatres of combat, where the pilots have generally excelled due to regular practice.

Small correction: In UK English, practice is a noun and practise is a verb. In America, practice is both and we don't have practise.

Thanks for clarifying. I'm American and I had never heard of practise in my life.

Same difference as licence vs license (vs licence)

I love this, however, in America we write excelled. I checked with Merriam-Webster, the Oxford Advanced American Dictionary, and with ChatGPT.

Ah! Perhaps it's only words like to counsel (counseled) or to libel (libeled); up in Canada here people usually write counselled or libelled.

Yes, in American English it depends on which syllable has stress. Compare:

dueled, paralleled, canceled, pedaled, but controlled, compelled, extolled, appalled

levered, snickered, but occurred, deferred

focused, biased, censused, but compressed, embussed, outgassed

worshiped, but entrapped (although even in America kidnapped seems more common than kidnaped—one of Webster’s less successful reforms)

How do you do italics in HN?

I've been here for more than a decade and can never figure out the formatting syntax.

> Text surrounded by asterisks is italicized. To get a literal asterisk, use \* or **.

See Formatting Options: https://news.ycombinator.com/formatdoc

Funny I'm Canadian and I thought it was aluminium and maneuvers

This makes me wonder if Canadian use full stop or period.

It's a bit of both!

"Period" tends to be used in day-to-day speech when referring to the punctuation; you'll hear "full stop" if it's meant to emphasize a previous statement (though not universally), like with "you'll do the dishes, full stop."

The line is drawn where ever the public puts it.

Generally, the correct spelling of a word is determined by those that use it. Canadians have used 'colour' for a long time. If enough people start using 'color', that will eventually be the correct spelling in Canada.