diff --git a/lib/src/MkLang.hs b/lib/src/MkLang.hs
new file mode 100644
index 000000000..f53613993
--- /dev/null
+++ b/lib/src/MkLang.hs
@@ -0,0 +1,48 @@
+module Main where
+
+-- Prepare a new resource directory. Usage:
+-- 1. $ cp german/*.gf dutch/
+-- 2. $ cd dutch/
+-- 3. $ runghc ../MkLang.hs Ger Dut
+-- AR 6/11/2009
+
+import System
+import List
+
+main = do
+  xx <- getArgs 
+  change xx
+
+change xx = case xx of
+  from:to:_ -> do
+     system "ls *.gf > files.tmp"
+     files <- readFile "files.tmp" >>= return . lines
+     mapM_ (changeFileName from to) files
+     system "ls *.gf > files.tmp"
+     files <- readFile "files.tmp" >>= return . lines
+     mapM_ (changeIdents from to) files
+     mapM_ commentOut files
+  comment -> do
+     files <- readFile "files.tmp" >>= return . lines
+     mapM_ commentOut files
+
+changeFileName from to file = system $ "mv " ++ file ++ " " ++ to_file where
+  to_file = take (length file - 3 - length from) (takeWhile (/='.') file) ++ to ++ ".gf"
+
+changeIdents from to = changeInFile changes
+ where
+   lg = length from
+   changes s = case s of
+     c:cs 
+       | take lg s == from -> to ++ changes (drop lg s)
+       | otherwise         -> c : changes cs
+     _ -> s
+
+commentOut = changeInFile comm where
+  comm s = let (hd,tl) = break (=='{') s in 
+    hd ++ "\n{\n" ++ unlines ["--" ++ l | l <- lines tl] ++ "\n}\n"
+
+changeInFile ch file = do
+  s <- readFile file
+  writeFile "gf.tmp" (ch s)
+  system $ "mv gf.tmp " ++ file