Keyboard layout 10 includes its own implementation of a mnemonic QWERTY-based input method for Russian, which does not fully rely on assigning a key to every Russian letter, but uses the sh, sc, ch, ya (ja), yu (ju), ye (je), yo (jo) combinations to input ш, щ, ч, я, ю, э, and ё respectively. Virtual (on-screen) Russian keyboards allow entering Cyrillic directly in a browser without activating the system layout. This virtual keyboard offers YaZhERT (яжерт) variant. Another virtual keyboard supports both traditional ("MS Windows" and Typewriter) and some phonetic keyboard layouts, including AATSEEL "Student", Mac OS X Phonetic Russian layout and
Dvorak Simplified Keyboard change. The Dvorak layout is often used in economics textbooks as a standard example of network effects, though this method has been criticized. Most keyboards are based on QWERTY patterns, despite the availability of other keyboard patterns, including the Dvorak. Although DSK is implemented in many languages other than English, there are still potential issues. Every Dvorak implementation for other languages has the same difficulties as for Roman characters. However, other (occidental) language orthographies can have other typing needs for optimization (many are very different from English). Because Dvorak Simplified Keyboard was optimized for the statistical distribution of letters of