Church Slavic keyboard layout and drivers Aleksandr A. Andreev∗ December 14, 2014 version 0.1 β ( file generated on December 28, 2014) Contents 1 Introduction 2 2 Philosophy of Input Method Design 2 3 Description of Chur Slavic Keyboard Layouts 5 3.1 Church Slavic ‘Standard’ Layout .................. 5 3.2 Russian Extended Layout ...................... 9 4 Installation Instructions 11 4.1 Microso Windows ......................... 11 4.2 Apple OS X .............................. 14 4.3 GNU/Linux .............................. 15 5 Editing the Keyboard Layout 17 5.1 Microso Windows ......................... 18 5.2 Apple OS X .............................. 19 5.3 GNU/Linux .............................. 19 6 Anowledgements 20 ∗ Comments may be directed to [email protected]. 1 1 Introduction Church Slavic (also called Church Slavonic, Old Church Slavonic or Old Slavonic; ISO 639-2 code cu) is a literary language used by the Slavic peoples; presently it is used as a liturgical language by the Russian Orthodox Church, other local Orthodox Churches, as well as various Byzantine-Rite Catholic and Old Ritualist communities. is document describes input methods that may be used to type Church Slavic text on a computer keyboard in different soware and operating system environments. Warning: these Church Slavic keyboard input methods provide support for a number of characters that are not currently available in the Unicode standard but have been accepted for encoding in a future version at provisional codepoints specified in the Unicode Pipeline. ese codepoints may change before their fi- nal encoding in Unicode, although such a change is not likely. You are strongly encouraged to periodically check for updates to the input methods, fonts, and cba relevant documentation.¹ is document is licensed under the Creative Commons Aribution-ShareAlike 4.0 International License. To view a copy of this license, visit the CreativeCom- mons website. 2 Philosophy of Input Method Design Much of the Church Slavic text now available electronically has been scanned and processed via Optical Character Recognition soware, or has been typeset using a variety of soware packages or add-ons, usually relying on ad hoc so- lutions. Another alternative is entering Church Slavic text via a Character Map utility; but this is inefficient and may cause improper rendering in some so- ware. e design of native keyboard entry mechanisms for Church Slavic has been elusive in the past because of the absence of a coherent model for encoding the writing system in Unicode and because of the writing system’s complexity, including the use of a variety of graphical variants for characters as well as a large number of diacritical marks and combining (superscript) leers. Creating an intuitive method for accessing these marks and leers is challenging. e challenge is further accentuated by the close historical relationship that Church Slavic has had with modern Russian and, hence, by the fact that any keyboard entry mechanism for Church Slavic needs to at least keep in mind the various ¹e latest information is available from the Slavonic Computing Initiative website. 2 Russian input methods if not to borrow from them in whole.² e input methods discussed in this documentation distinguish between two types of users: a profes- sional user is someone who needs to typeset a relatively large volume of Church Slavic text, modern or historical, and is willing to invest some time to learn a special keyboard input method that would allow typeseing Church Slavic text in an ‘optimal’ manner. On the other hand, an occasional user is typeseing text in Russian for the vast majority of his time and only needs access to Church Slavic characters on a rare occasion to typeset a small amount of (usually mod- ern liturgical) text. We operate with the basic assumption that a professional user will be using the touch typing technique and needs an optimized layout for this ten finger method. A user who relies on ‘hunt and peck’ typing is by definition less concerned with keyboard layout optimization, though some intuitive layout of keys may still be desirable. e design of an ‘optimal’ keyboard layout is not a scientific process. Nonetheless, some general principles of optimizing a layout for the touch typing technique can be identified: ‣ limit the use of weak fingers (lile finger and ring finger) ‣ limit the use of the boom row of the keyboard ‣ increase the use of the home row ‣ limit the finger travel distance between two keystrokes ‣ balance the use of the le and right hand Keeping in mind these principles, one can, in fact, aempt to write down a mathematical model for keyboard entry. ere are, in fact, a number of projects aempting to do just such a thing, and then to choose a keyboard method that optimizes the parameters of their mathematical model. One such example is the Carpalx keyboard optimization algorithm.³ In mathematical language, one could write down the keyboard optimization problem as: min E(·|C(x);M(x)) (1) C(x) where x is the vector of Church Slavic characters; C(x) is the matrix represent- ²We discuss only the Russian input methods because Russian is by far the most widely used language recorded with the Cyrillic script and so with high probability both ecclesiastical and academic users of Church Slavic are accustomed to a Russian input method (although they may be accustomed to different Russian input methods depending on their location and background, as we discuss below). However, all of the approaches to designing a Church Slavic keyboard layout that we outline in this documentation could be used to design a keyboard layout based on a Ukrainian, Bulgarian, Serbian, etc., input method for users of other linguistic and ethnic backgrounds. ³See hp://mkweb.bcgsc.ca/carpalx/ for more information. 3 ing their configuration on the keyboard; M(x) is the corpus of existing Church Slavic text, which provides information about the rules of the Church Slavic writ- ing system; and the function E(·) is some measure of typing effort. is mini- mization problem can be solved in principle given proper specifications for E(·); but we need not do that here, since, given the relationship between Church Slavic and Russian, we are not in need of a fully optimized solution. In fact, instead of solving Problem 1, we are actually looking for the solution to a somewhat more complex problem: min E(·|L(C(x) − C(r));C(x);M(x)) given L(·) ≤ L¯ (2) C(x) where L(·) is the cost of learning a new keyboard layout, C(r) is the matrix of the Russian keyboard layout, and L¯ is some maximal learning cost that the user is willing to tolerate. ough in principle this constrained optimization problem may also be solved, given that we have no adequate model for the function L(·), and given the fact the L¯ is not constant but depends on the user’s preferences, we will not solve Problem 2, but will only rely on its statement for intuition. In any case, we cannot use Carpalx since it is designed only for a two-level keyboard layout (Level 1 and Shi), and our keyboard layouts will use four levels as well as dead keys (see below). Given Problem 2, a number of observations are in order. First, generally speaking we have L¯P > L¯O, in other words the professional user is willing to endure a much higher cost of learning a new keyboard layout than an occa- sional user. Second, we see that the typing effort E(·) is dependent on the corpus of Church Slavic text, more specifically, on the frequency with which the vari- ous characters occur in Church Slavic. It would be a mistake to assume that the character frequency for Church Slavic words is similar to modern Russian, and, as the chart in Figure 2 demonstrates, the most widely used Church Slavic char- acter is in fact the acute accent ◌́. Observe also that the hard sign (ъ) occurs quite frequently, although it is hardly ever encountered in Russian text, and hence on the Russian keyboard has been relegated to the \. key. Note also that capital leers in Church Slavic are quite infrequent, only used at the beginning of a sen- tence and in titling. On the other hand, Church Slavic uses a variety of graphical variant characters, and since L(·) is also a function of (C(x) − C(r)) — in other words, the cost of learning is dependent on the difference between the Russian and Church Slavic layouts — there needs to be an intuitive way to position these graphical variants on the keyboard. For example, the keyboard positions for ѻ and ᲂ should somehow be related to the position of о and the positions for ѿ, ꙍ, 4 and ѽ should probably have some relationship with ѡ. Given all of this intuition, we are now ready to present two different key- board layouts that may be used to type Church Slavic text on the keyboard. e first is a ‘standard’ layout designed specifically for use by the professional user. ough the Russian ЙЦУКЕН layout has been taken as a starting point, it has been significantly reconfigured in order to minimize the typing effort E(·) by making a minimal and intuitive set of changes (C(x) − C(r)). On the other end of the spectrum is the Russian Extended keyboard layout, which basically leaves the ЙЦУКЕН layout intact for typing modern Russian text, but adds Church Slavic characters on the third and fourth levels in some intuitive manner. is second layout is designed for the occasional user. 3 Description of Chur Slavic Keyboard Layouts 3.1 Chur Slavic ‘Standard’ Layout is keyboard layout is a four-level layout with two dead keys.