Index: gc_lang/fr/modules-js/phonet.js
==================================================================
--- gc_lang/fr/modules-js/phonet.js
+++ gc_lang/fr/modules-js/phonet.js
@@ -82,31 +82,36 @@
             }
         }
         return aSelect;
     },
 
-    isSimilAs: function (sWord, sSimil) {
-        // return True if <sWord> phonetically similar to <sSimil> (<sWord> tested with several casing)
-        if (!sWord) {
-            return false;
-        }
-        let lSimils = this.getSimil(sSimil);
-        if (lSimils.length == 0) {
-            return false;
-        }
-        if (lSimils.includes(sWord)) {
-            return true;
+    _getSetNumber (sWord) {
+        // return the set number where <sWord> belongs, else -1
+        if (this._dWord.has(sWord)) {
+            return this._dWord.get(sWord);
         }
         if (sWord.slice(0,1).gl_isUpperCase()) {
-            if (lSimils.includes(sWord.toLowerCase())) {
-                return true;
+            if (this._dWord.has(sWord.toLowerCase())) {
+                return this._dWord.get(sWord.toLowerCase());
             }
-            if (sWord.gl_isUpperCase() && lSimils.includes(sWord.gl_toCapitalize())) {
-                return true;
+            if (sWord.gl_isUpperCase() && this._dWord.has(sWord.gl_toCapitalize())) {
+                return this._dWord.get(sWord.gl_toCapitalize());
             }
         }
-        return false;
+        return -1;
+    },
+
+    isSimilAs: function (sWord, sSimil) {
+        // return True if <sWord> phonetically similar to <sSimil> (<sWord> tested with several casing)
+        if (!sWord || !sSimil) {
+            return false;
+        }
+        let n = this._getSetNumber(sWord);
+        if (n == -1) {
+            return false;
+        }
+        return n == this._getSetNumber(sSimil);
     }
 };
 
 
 // Initialization

Index: gc_lang/fr/modules/phonet.py
==================================================================
--- gc_lang/fr/modules/phonet.py
+++ gc_lang/fr/modules/phonet.py
@@ -50,21 +50,26 @@
         for sMorph in _dMorph.get(sSimil, []):
             if re.search(sPattern, sMorph):
                 aSelect.add(sSimil)
     return aSelect
 
+
+def _getSetNumber (sWord):
+    "return the set number where <sWord> belongs, else -1"
+    if sWord in _dWord:
+        return _dWord[sWord]
+    if sWord[0:1].isupper():
+        if sWord.lower() in _dWord:
+            return _dWord[sWord.lower()]
+        if sWord.isupper() and sWord.capitalize() in _dWord:
+            return _dWord[sWord.capitalize()]
+    return -1
+
 
 def isSimilAs (sWord, sSimil):
     "return True if <sWord> phonetically similar to <sSimil> (<sWord> tested with several casing)"
-    if not sWord:
-        return False
-    lSimils = getSimil(sSimil)
-    if not lSimils:
-        return False
-    if sWord in lSimils:
-        return True
-    if sWord[0:1].isupper():
-        if sWord.lower() in lSimils:
-            return True
-        if sWord.isupper() and sWord.capitalize() in lSimils:
-            return True
-    return False
+    if not sWord or not sSimil:
+        return False
+    n = _getSetNumber(sWord)
+    if n == -1:
+        return False
+    return n == _getSetNumber(sSimil)