From d6c5dbc925e63bebc048356c4a54a1ad6b364014 Mon Sep 17 00:00:00 2001
From: Lars-Dominik Braun
- The layout proposed uses four layers and assumes a 102/105 key ISO
- keyboard common in Europe to accomodate the shift keys necessary.
+ The layout proposed uses four shift layers in a way inspired by Neo2.
+
+ Thus it assumes a 102/105
+ key ISO keyboard common in Europe – but also available in Arab
+ countries – to accommodate for the necessary shift keys.
These are in order: Shift on the left and
right, caps lock on the left and the
rightmost key in the middle row, the
- key right of the left shift key and the key labeled Alt Gr to
+ key right to the left shift key and the key labeled Alt Gr to
the right of the spacebar.
Symbols are assigned to the four layers by their function: punctuation, diacritics, other.
Apple, for instance, provides an Arabic
+ hardware keyboard with this physical layout. But both variants,
+ 101/104 key and 102/105 key devices, seem to exist in the Arab
+ world.
The first layer was optimized using an extended reimplementation of carpalx.
@@ -299,10 +313,10 @@
(This is This is a
common way of arranging brackets, because most algorithms ignore
- human desire for symmetry.)
+
-
@@ -317,6 +331,59 @@ typing load, but naturally the left middle finger is used more frequently due to its assignment to the letter alif.
+ ++ The layout targets Quaranic and Modern Standard Arabic (MSA), also called Fusha + (الفصحى), only. + + Dialectical Arabic (العامية) is mainly a spoken + language, although with the rise of social media sites like Twitter and + Facebook this is changing. + + For now however it’s not an optimization target due to the lack of a + good, representative corpus. +
+ ++ Designing the layout to be compose-based has both benefits and + disadvantages. + + Compose-based mainly means the hamza ء + is treated like an optional diacritic for Alef, Waw and Yah instead of + viewing Alef-Hamza, Waw-Hamza and Yah-Hamza as precombined, atomic + units. + + Although أ and ا are not the same, the hamza can be dropped if the + writer’s intention is unambigiously inferable from context. + + Thus it makes sense to provide hamza as a combining character on the + keyboard. + + Additionally it uses two keys less than precombining it with its stems, + allowing the entire alphabet plus hamza diacritic to fit on a single + keyboard layer. + + However, there is a cost to this approach: + All hamza variants account for {{ + '%.1f'|format(layoutstats['ar-osx'].hamzaImpact*100) }}% of button + combinations. + + Splitting hamza and from its stem means doubling the total number of + button combinations and thus button presses, decreasing scores like + words per minute (WPM) slightly. + + Splitting Alef and Alef-Hamza could also reduce pressure on left middle + finger and allow for more even distribution, since {{ + layoutstats['ar-osx'].hamzaOnAlef|fraction }}th of all Alef + uses are with Hamza. +
+See for example section 3.3 of Buckwalter’s Issues in Arabic Morphological Analysis. +
+