diff --git a/autoload/duzzle.vim b/autoload/duzzle.vim
index 78ab181..48acabd 100644
--- a/autoload/duzzle.vim
+++ b/autoload/duzzle.vim
@@ -36,7 +36,7 @@ let s:message = s:LM.new(s:message_path)
 let s:start_message = s:message.get('start_message')
 if s:P.is_string(s:start_message) &&
   \s:start_message ==# 'start_message'
-  call s:message.load('ja')
+  call s:message.load(get(g:, 'duzzle_language', 'en'))
 endif
 
 function! s:complete_experiment(optlead, cmdline, cursorpos)
diff --git a/autoload/leaderf/duzzle.vim b/autoload/leaderf/duzzle.vim
new file mode 100644
index 0000000..b1ecc76
--- /dev/null
+++ b/autoload/leaderf/duzzle.vim
@@ -0,0 +1,11 @@
+function! leaderf#duzzle#source(args) abort "{{{
+	let l:duzzles = []
+	for l:duzzle_puzzle in duzzle#puzzle_list('_')
+		let l:duzzles += [matchstr(l:duzzle_puzzle['name'], '\d\+')]
+	endfor
+	return l:duzzles
+endfunction "}}}
+
+function! leaderf#duzzle#accept(line, args) abort "{{{
+	execute 'DuzzleStart ' . a:line
+endfunction "}}}
diff --git a/plugin/duzzle.vim b/plugin/duzzle.vim
index f6bf0b6..a2dd538 100644
--- a/plugin/duzzle.vim
+++ b/plugin/duzzle.vim
@@ -37,6 +37,20 @@ command! -nargs=* -complete=customlist,duzzle#complete
 let g:duzzle_default_experiment_name = '_'
 let g:duzzle_default_room_number     = '1'
 
+if !exists('g:Lf_Extensions')
+  let g:Lf_Extensions = {}
+endif
+
+let g:Lf_Extensions.duzzle = {
+      \ 'source': 'leaderf#duzzle#source',
+      \ 'accept': 'leaderf#duzzle#accept',
+      \ 'highlights_def': {
+      \ 'Lf_hl_duzzleTitle': '.*',
+      \ },
+      \ 'highlights_cmd': [
+      \ 'hi link Lf_hl_duzzleTitle Title',
+      \ ],
+      \ }
 
 let &cpo = s:save_cpo
 unlet s:save_cpo