other instances used the US version

doc/Language/subscripts.pod6

@@ -651,7 +651,7 @@ However, we may prefer to be less strict about user input and instead take
 care of sanitizing the field values ourselves. In that case, we can remove
 the C<StrOrArrayOfStr> type constraint on C<%!fields>, and replace our
 C<AT-KEY> implementation with one that returns a custom C<Proxy> container
-which takes care of sanitising values on assignment:
+which takes care of sanitizing values on assignment:
 
     multi method AT-KEY (::?CLASS:D: $key) is rw {
         my $element := %!fields{normalize-key $key};