diff --git a/src/GF/Compile/GetGrammar.hs b/src/GF/Compile/GetGrammar.hs
index 41c2c063d..62826746c 100644
--- a/src/GF/Compile/GetGrammar.hs
+++ b/src/GF/Compile/GetGrammar.hs
@@ -44,6 +44,7 @@ import GF.Infra.ReadFiles ----
 
 import Data.Char (toUpper)
 import Data.List (nub)
+import qualified Data.ByteString.Char8 as BS
 import Control.Monad (foldM)
 import System (system)
 
@@ -61,14 +62,14 @@ getSourceModule opts file0 = do
   let string = case getOptVal opts uniCoding of
         Just "utf8" -> decodeUTF8 string0
         _ -> string0
-  let tokens = myLexer string
+  let tokens = myLexer (BS.pack string)
   mo1  <- ioeErr $ err2err $ pModDef tokens
   ioeErr $ transModDef mo1
 
 getSourceGrammar :: Options -> FilePath -> IOE SourceGrammar
 getSourceGrammar opts file = do
   string    <- readFileIOE file
-  let tokens = myLexer string
+  let tokens = myLexer (BS.pack string)
   gr1  <- ioeErr $ err2err $ pGrammar tokens
   ioeErr $ transGrammar gr1
 
@@ -117,7 +118,7 @@ ioeEErr = ioeErr . err2err
 -- change them by turning the final letter to upper case.
 --- There is a risk of clash. 
 oldLexer :: String -> [L.Token]
-oldLexer = map change . L.tokens where
+oldLexer = map change . L.tokens . BS.pack where
   change t = case t of
     (L.PT p (L.TS s)) | elem s newReservedWords -> 
         (L.PT p (L.TV (init s ++ [toUpper (last s)])))
diff --git a/src/GF/Compile/PGrammar.hs b/src/GF/Compile/PGrammar.hs
index 1c6f0b411..e4e60d623 100644
--- a/src/GF/Compile/PGrammar.hs
+++ b/src/GF/Compile/PGrammar.hs
@@ -29,10 +29,11 @@ import GF.Grammar.Macros
 import GF.Grammar.MMacros
 
 import GF.Data.Operations
+import qualified Data.ByteString.Char8 as BS
 
 pTerm :: String -> Err Term
 pTerm s = do
-  e <- err2err $ pExp $ myLexer s
+  e <- err2err $ pExp $ myLexer (BS.pack s)
   transExp e
 
 pTrm :: String -> Term