Vim has a built-in Dvorak keymap that you can load with :se kmp=dvorak<cr>. this way when you type on a QWERTY keyboard it's as if it were a Dvorak keyboard. although brace for a huge mindfuck: the keymap is only active in searches and in insert mode, so all Vim commands are still QWERTY. the command-line is also still QWERTY, but you can switch it to Dvorak with |c_CTRL-^|

see |mbyte-keymap| and |language-mapping| for more information