Index: graphspell-js/char_player.js
==================================================================
--- graphspell-js/char_player.js
+++ graphspell-js/char_player.js
@@ -253,10 +253,14 @@
         ["OA", ["OI",]],
         ["oe", ["œ",]],
         ["OE", ["Œ",]],
         ["oi", ["oa", "oie"]],
         ["OI", ["OA", "OIE"]],
+        ["gg", ["gu",]],
+        ["GG", ["GU",]],
+        ["gu", ["gg",]],
+        ["GU", ["GG",]],
         ["ph", ["f",]],
         ["PH", ["F",]],
         ["qu", ["q", "cq", "ck", "c", "k"]],
         ["QU", ["Q", "CQ", "CK", "C", "K"]],
         ["ss", ["c", "ç"]],

Index: graphspell/char_player.py
==================================================================
--- graphspell/char_player.py
+++ graphspell/char_player.py
@@ -236,10 +236,14 @@
     "EI": ("AI", "É", "È", "Ê", "Ë"),
     "ch": ("sh", "c", "ss"),
     "CH": ("SH", "C", "SS"),
     "ct": ("x", "cc"),
     "CT": ("X", "CC"),
+    "gg": ("gu",),
+    "GG": ("GU",),
+    "gu": ("gg",),
+    "GU": ("GG",),
     "oa": ("oi",),
     "OA": ("OI",),
     "oe": ("œ",),
     "OE": ("Œ",),
     "oi": ("oa", "oie"),