It’s a convention taken over from paper forms, and the reason is likely the adjacency benefit I mentioned. Consider the analogous radio buttons, which work like a bullet list in terms of layout. A bullet list with the bullets on the right would be weird (in LTR languages).

Also compare with todo lists (todo apps), or selecting items from a listing. The check control is always on the left. For example in iOS Mail: https://support.apple.com/en-us/HT208661 Or checklists in iOS Notes: https://support.apple.com/en-us/HT209365

Furthermore, checkboxes can have subordinate controls, like in this example: https://learn.microsoft.com/en-us/windows/win32/uxguide/imag...

Having the checkbox at the beginning of what is enabled/disabled just makes sense, similar to how in an `if` statement you have the condition at the beginning instead of at the end.

That's not what the word "need" means.

English text aligns on the left. So the checkboxes need to be on the left to be close to the text.

If checkboxes are on the right, they are either far away from the text or (I shudder to imagine) horizontally misaligned.

While that does make sense, a grid layout helps solve some of that - though it could be hard to keep track of what checkbox belongs to what row. I'm not arguing that we switch up where checkboxes go, I'm just asking if our assumptions are as valid as we think they are.