Here is an attempt at a centered compromise layout:
http://www.keyboard-layout-editor.com/#/layouts/4aacf9586543ff0686f4ef55309c7e11
Some people may question the dedicated keys for ` ~ and to a lesser extent ' " (apostrophe is the most important punctuation symbol in casual English, double quote in formal English after comma, period and hyphen/dash), but those are crucial to compensate for the lack of P+2 and L+2 keys, since they have a double use as dead diacritics in my layout proposal. After all, remapping P+2 and L+2 only gives you four extra letters. Many languages need much more than that anyway.
Pyra+' is dead acute accent, so the French can make their é, the Bulgarians, Catalan, Dutch, Portuguese, Spanish, Norwegian, Swedish, Danish and Welsh can add stress or emphasis to their vowels and disambiguate some words, the Czech, Hungarians, Irish and Slovaks can mark their long vowels, the Polish, Serbo-Croatian and Macedonians can indicate their palatalization, and the Faroese, Icelandic, Turkmen, Pashto and Northern Sámi can make their extra letters. Even in English it is used for French loan words like
attaché,
blasé,
canapé,
cliché,
communiqué,
café,
décor,
déjà vu,
détente,
élite,
entrée,
exposé,
mêlée,
fiancé,
fiancée,
papier-mâché,
passé,
pâté,
piqué,
plié,
repoussé,
résumé,
risqué,
sauté,
roué,
séance,
naïveté,
toupée and
touché. Also Japanese loan words like
saké and
Pokémon are spelled with acute accents.
Pyra+" is dead umlaut (aka diaeresis or trema), so the Germans can make their ü ä ö, as well as the Azerbaijani, Estonian, Finnish, Hungarian, Slovak, Swedish and Turkish. It is also used to indicate that two adjacent vowels are pronounced separately, e.g. in names like
Chloë and
Zoë and in some words in English (
naïve for example), French, Dutch, Welsh, and Catalan.
Pyra+` is dead grave accent, so the French can make their à è ù, but it is also used in Italian, Bulgarian, Macedonian, Catalan, Norwegian (e.g.
og vs
òg), Portuguese, Welsh, Scottish Gaelic, Vietnamese, Breton, and Dutch. In English it is only used in poetry and lyrics and in some loaned expressions like
vis-à-vis,
pièce de résistance and
crème brûlée. In LaTeX quotes are written using
``this syntax''.
Pyra+~ is dead tilde, so the Spanish can make their ñ, but it is also used in Portuguese (on vowels), so it is pretty much necessary in most of South America. Also, Estonian, Basque, Breton and Vietnamese. In English it is only used in loan words like
jalapeño,
piña colada,
piñata, and
El Niño.
Pyra+^ is dead circumflex (for â ê î ô û), Pyra+, is dead cedilla (for ç ş), ogonek (for ą ę į ų ) and comma (for ţ ķ ļ ņ ģ), Pyra+. is dead dot (for ċ ġ ė ż), Pyra+* is dead ring (for å ů), Pyra+% is dead stroke (for ø đ ħ ł), Pyra+( is dead breve (for ă ğ), Pyra+V is dead caron/háček (for č š ž ř ď ľ ě ǧ ȟ).
That covers pretty much every language that uses a Latin-based alphabet. Just two are missing: macron and hungarumlaut. I propose the following scheme: tilt your head to the right (as if you're looking at a smiley, but the other way around) and look at the symbol on the right of the key. Now press Shift+Pyra (both left shoulder buttons) to get that as a dead key, according to this scheme (example given with the letter a):
A\ S| D/ F< G> 9( 0) X¤ 8* N= .:
á ā à ǎ â ă ȃ å å a̋ ä
I think that with these provisions for international letters (basically accented letter can be produced with just two thumb presses), we don't really need the P+2 and L+2 positions anymore. Of course if you need particular letters frequently, you may still want to map them to a single thumb press combo, e.g. if you're Norwegian, you could do for example something like Pyra+* is Å (immediately, not dead key ° that still has to be followed by A), Shift+/ is Ø, Shift+\ is Æ, or whatever is convenient for you to remember. If you're German and you can live without Shift+F8 and Shift+F10, then you could for example map Pyra+Shift+{UOAS} to ÜÖÄß. If you're French, you may want to put the numbers at Pyra+number and map those keys to é è ç à in their usual AZERTY spots, with dedicated primary keys for ù and dead circumflex in between somewhere. And so on.
But as a base, default layout, I could certainly live with this. I like the symmetry between Del and Backspace and between grave and acute. The correct alignment of the number row w.r.t. the letter rows is also good to have.
