diff --git a/NLP/Minimorph/English.hs b/NLP/Minimorph/English.hs
--- a/NLP/Minimorph/English.hs
+++ b/NLP/Minimorph/English.hs
@@ -1,8 +1,11 @@
-{-# LANGUAGE OverloadedStrings, ViewPatterns #-}
+{-# LANGUAGE ViewPatterns #-}
 -- TODO : learn how to use Functional Morphology instead
 -- |Simple default rules for English morphology
 module NLP.Minimorph.English where
 
+-- Only needed for older GHC, but let's avoid CPP for this instance.
+import Data.Monoid ((<>))
+
 import           Data.Char (isSpace, isUpper, toLower)
 import           Data.Text (Text)
 import qualified Data.Text as T
@@ -100,14 +103,16 @@
     | hasSibilantSuffix x   = sibilant_o
     | hasCoSuffix x         = sibilant_o
     | hasCySuffix x         = y_final
-    | "f"  `T.isSuffixOf` x = f_final
+    | "ff" `T.isSuffixOf` x = ff_final  -- quite often not the case
+    | "f" `T.isSuffixOf` x  = f_final   -- but this one as well, so both needed
     | otherwise             = plain
   where
     plain      = x            <> "s"
     sibilant_o = x            <> "es"
     y_final    = T.init x     <> "ies"
     f_final    = T.init x     <> "ves"
-    thesis     = tDropEnd 2 x <> "es"
+    ff_final   = T.dropEnd 2 x <> "ves"
+    thesis     = T.dropEnd 2 x <> "es"
 
 -- | Heuristics for 3rd person singular and past participle
 --   for an unknown regular verb. Doubling of final consonants
@@ -242,12 +247,12 @@
 
 -- | Last two letters are a consonant and \'y\'.
 hasCySuffix :: Text -> Bool
-hasCySuffix (T.unpack . tTakeEnd 2 -> [x, 'y']) = isConsonant x
+hasCySuffix (T.unpack . T.takeEnd 2 -> [x, 'y']) = isConsonant x
 hasCySuffix _ = False
 
 -- | Last two letters are a consonant and \'o\'.
 hasCoSuffix :: Text -> Bool
-hasCoSuffix (T.unpack . tTakeEnd 2 -> [x, 'o']) = isConsonant x
+hasCoSuffix (T.unpack . T.takeEnd 2 -> [x, 'o']) = isConsonant x
 hasCoSuffix _ = False
 
 -- | Is a vowel.
diff --git a/NLP/Minimorph/Util.hs b/NLP/Minimorph/Util.hs
--- a/NLP/Minimorph/Util.hs
+++ b/NLP/Minimorph/Util.hs
@@ -1,20 +1,13 @@
-{-# LANGUAGE OverloadedStrings #-}
 -- | Text utility functions.
 module NLP.Minimorph.Util
- ( tTakeEnd, tDropEnd, (<>), (<+>), tshow )
+ ( (<+>), tshow )
  where
 
+-- Only needed for older GHC, but let's avoid CPP for this instance.
 import Data.Monoid ((<>))
-import Data.Text (Text)
-import qualified Data.Text as T
 
--- | @tTakeEnd n t@ returns the last @n@ letters of @t@.
-tTakeEnd :: Int -> Text -> Text
-tTakeEnd n t = T.drop (T.length t - n) t
-
--- | @tDropEnd n t@ drops the last @n@ letters of @t@.
-tDropEnd :: Int -> Text -> Text
-tDropEnd n x = T.take (T.length x - n) x
+import           Data.Text (Text)
+import qualified Data.Text as T
 
 infixr 6 <+>  -- matches Monoid.<>
 -- | Separated by space unless one of them is empty (in which case just
diff --git a/minimorph.cabal b/minimorph.cabal
--- a/minimorph.cabal
+++ b/minimorph.cabal
@@ -5,7 +5,7 @@
 -- PVP summary:      +-+------- breaking API changes
 --                   | | +----- minor or non-breaking API additions
 --                   | | | +--- code changes with no API change
-version:             0.2.1.0
+version:             0.2.2.0
 synopsis:            English spelling functions with an emphasis on simplicity.
 description:         A set of simplistic functions capturing the more regular
                      parts of English spelling (for generation, not parsing).
@@ -38,18 +38,20 @@
                        NLP.Minimorph.Util
 
   build-depends:       base < 5
-               ,       text
+               ,       text >= 1.1.1
 
   default-language:   Haskell2010
+  default-extensions: OverloadedStrings
   if impl(ghc >= 8.0)
   {
   default-extensions: MonoLocalBinds, ScopedTypeVariables, OverloadedStrings
                       BangPatterns, RecordWildCards, NamedFieldPuns, MultiWayIf,
                       LambdaCase, DefaultSignatures, InstanceSigs,
-                      MonadFailDesugaring, StrictData, CPP
-  ghc-options:        -Wall -Wcompat -Worphans -Wincomplete-uni-patterns -Wincomplete-record-updates -Wmissing-home-modules -Widentities -Wredundant-constraints
+                      PatternSynonyms, StrictData, CPP
+  other-extensions:   ViewPatterns
+  ghc-options:        -Wall -Wcompat -Worphans -Wincomplete-uni-patterns -Wincomplete-record-updates -Wmissing-home-modules -Widentities -Wredundant-constraints -Wpartial-fields
   ghc-options:        -Wall-missed-specialisations
-  ghc-options:        -fno-ignore-asserts -fexpose-all-unfoldings -fspecialise-aggressively
+  ghc-options:        -fno-ignore-asserts -fexpose-all-unfoldings -fspecialise-aggressively -fsimpl-tick-factor=200
   }
 
 test-suite test-minimorph
@@ -64,13 +66,15 @@
                ,       test-framework-hunit
                ,       text
   default-language:   Haskell2010
+  default-extensions: OverloadedStrings
   if impl(ghc >= 8.0)
   {
   default-extensions: MonoLocalBinds, ScopedTypeVariables, OverloadedStrings
                       BangPatterns, RecordWildCards, NamedFieldPuns, MultiWayIf,
                       LambdaCase, DefaultSignatures, InstanceSigs,
-                      MonadFailDesugaring, StrictData, CPP
-  ghc-options:        -Wall -Wcompat -Worphans -Wincomplete-uni-patterns -Wincomplete-record-updates -Wmissing-home-modules -Widentities -Wredundant-constraints
+                      PatternSynonyms, StrictData, CPP
+  ghc-options:        -Wall -Wcompat -Worphans -Wincomplete-uni-patterns -Wincomplete-record-updates -Wmissing-home-modules -Widentities -Wredundant-constraints -Wpartial-fields
   ghc-options:        -Wall-missed-specialisations
-  ghc-options:        -fno-ignore-asserts -fexpose-all-unfoldings -fspecialise-aggressively
+  ghc-options:        -fno-ignore-asserts -fexpose-all-unfoldings -fspecialise-aggressively -fsimpl-tick-factor=200
+  ghc-options:        -threaded -rtsopts
   }
diff --git a/test/NLP/Minimorph/EnglishTest.hs b/test/NLP/Minimorph/EnglishTest.hs
--- a/test/NLP/Minimorph/EnglishTest.hs
+++ b/test/NLP/Minimorph/EnglishTest.hs
@@ -1,5 +1,3 @@
-{-# LANGUAGE OverloadedStrings #-}
-
 module NLP.Minimorph.EnglishTest where
 
 import           Data.Text (Text)