diff --git a/Text/Inflections/Ordinal.hs b/Text/Inflections/Ordinal.hs
index 7aaf2e8..fe46675 100644
--- a/Text/Inflections/Ordinal.hs
+++ b/Text/Inflections/Ordinal.hs
@@ -21,7 +21,7 @@ where
 -- "nd"
 -- >>> ordinal 10
 -- "th"
-ordinal :: Integer -> String
+ordinal :: Integral a => a -> String
 ordinal number
         | remainder100 `elem` [11..13] = "th"
         | remainder10 == 1             = "st"
@@ -41,5 +41,5 @@ ordinal number
 -- "2nd"
 -- >>> ordinalize 10
 -- "10th"
-ordinalize :: Integer -> String
+ordinalize :: (Integral a, Show a) => a -> String
 ordinalize n = show n ++ ordinal n
diff --git a/stack.yaml b/stack.yaml
index d3d9480..1be6cbc 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,3 +1,5 @@
 resolver: lts-6.4
 packages:
 - '.'
+extra-deps:
+- megaparsec-5.0.0
diff --git a/test/Text/Inflections/OrdinalSpec.hs b/test/Text/Inflections/OrdinalSpec.hs
index 6200e40..910eb94 100644
--- a/test/Text/Inflections/OrdinalSpec.hs
+++ b/test/Text/Inflections/OrdinalSpec.hs
@@ -26,38 +26,38 @@ spec = do
 one :: Spec
 one =
   it "returns the ordinal for 1" $
-    ordinal 1 `shouldBe` "st"
+    ordinal (1 :: Integer) `shouldBe` "st"
 
 two :: Spec
 two =
   it "returns the ordinal for 2" $
-    ordinal 2 `shouldBe` "nd"
+    ordinal (2 :: Integer) `shouldBe` "nd"
 
 thousands :: Spec
 thousands = do
   it "returns the ordinal for 1002" $
-    ordinal 1002 `shouldBe` "nd"
+    ordinal (1002 :: Integer) `shouldBe` "nd"
   it "returns the ordinal for 1003" $
-    ordinal 1003 `shouldBe` "rd"
+    ordinal (1003 :: Integer) `shouldBe` "rd"
 
 negatives :: Spec
 negatives = do
   it "returns the ordinal for -11" $
-    ordinal (-11) `shouldBe` "th"
+    ordinal (-11 :: Integer) `shouldBe` "th"
   it "returns the ordinal for -1021" $
-    ordinal (-1021) `shouldBe` "st"
+    ordinal (-1021 :: Integer) `shouldBe` "st"
 
 fullOrdinals :: Spec
 fullOrdinals = do
   it "returns the full ordinal for 1" $
-     ordinalize 1 `shouldBe` "1st"
+    ordinalize (1 :: Integer) `shouldBe` "1st"
   it "returns the full ordinal for -1021" $
-     ordinalize (-1021) `shouldBe` "-1021st"
+    ordinalize (-1021 :: Integer) `shouldBe` "-1021st"
 
 ordinalReturnsNotEmpty :: Spec
 ordinalReturnsNotEmpty =
   it "never returns empty" $ property $
-    property <$> not . null . ordinal
+    property <$> not . null . (ordinal :: Integer -> String)
 
 ordinalizeContainsTheSameNumber :: Spec
 ordinalizeContainsTheSameNumber =