Fix bug: language switch command "\~" failed to detect language id which contains '-'

Support language switch for language ids, 'Japanese-en', 'Korean-en', 'Serbian-Cyrillic', and similer langauge ids.
Fixed typos in comments.
Merge pull request #255 from orbitcowboy/master

Fixed typos in comments.
Merge pull request #254 from kbinani/language_switch_command

Fix bug: language switch command skipped when langauge id contains "-" letter