Mark Davis wrote:
> In practice, the keyboards I have seen with an additional level > generally need and use a pair of additional levels. The issue is that > if a lowercase character x is on a level, then you want to be able to > get the uppercase version of it X by using that same level plus a > shift key. So in practice you end up with plain, plain+shifted, > alternate, alternate+shifted.
Keyboards that follow this peculiar requirement of ISO 9995 (three levels but not four) pay a penalty when there are too many letters (accented or otherwise) to fit in Levels 1 and 2, and the national custom is *not* to use combining dead keys. Either the capital and small versions of a letter must be on different keys within the same level (Polish puts Ä' at AltGr+S and Ä at AltGr+D) or the capital letter is not assigned to a key at all (Italian has è and é but not È or É, which forces users to type E' when starting a sentence with "It is").
[Alain] There is no penalty, you can have as many groups as you want. Do not make a confusion with PC implementations which are limited to 3 levels in only one group, and where no group 2 is implemented.
On the Canadian keyboard, typical upper and lower case French letters are available in group 1, but Scandinavian upper and lower case letters are available in group 2. (and in fact the French ligatures OE too). There is no penalty. Easy.
Alain LaBonté
Québec
