Whereas vi's keystroke language follows verb-object order, Kakoune inverts that by following object-verb order. In real terms, that means you make a selection (object) before deciding what to do (verb) with it.
The object might be a character, word, sentence, paragraph, parenthetical, regular expression, you name it; the verb might be delete, yank (copy), change, indent, or even transformative operations like lint, format, uppercase, etc.
In Kakoune, it is with this reversed grammar, this postfix notation, that you interactively sweep up a group or groups of characters before acting on them. That way if your object isn’t quite right, you can immediately correct it without having to undo and redo your verb.
-- Gregory Chamberlain1