The Five Eyes rationalize that it's perfectly normal to spy on enemies together, and share information, given that the Five Eyes nations all speak English.
Well it's a little deeper than that isn't it? There is a lot more common ground than just the language, like 4 of those countries are CommonWealth realms with the Queen as the head of state, so there's a big distinction right there. They also have similar military structures or processes since WW2, a history of major collaborations (like the Manhattan project between Canada, UK and US).
The Five Eyes rationalize that it's perfectly normal to spy on enemies together, and share information, given that the Five Eyes nations all speak English.
https://en.wikipedia.org/wiki/Five_Eyes