diff --git a/tkfilebrowser/constants.py b/tkfilebrowser/constants.py
index 05346be..256ba59 100644
--- a/tkfilebrowser/constants.py
+++ b/tkfilebrowser/constants.py
@@ -79,10 +79,53 @@
 IM_RECENT_24 = os.path.join(PATH, "images", "recent_24.png")
 
 # ---  translation
-try:
-    LANG = locale.getdefaultlocale()[0]
-except ValueError:
-    LANG = 'en'
+def _get_locale_messages_category():
+    try:
+        category = locale.LC_MESSAGES
+    except AttributeError:
+        # LC_MESSAGES may not be available on non-POSIX OSes
+        category = locale.LC_ALL
+    return category
+
+
+class _different_locale:
+    def __init__(self, _locale):
+        self.locale = _locale
+        self.oldlocale = None
+        self.category = _get_locale_messages_category()
+
+    def __enter__(self):
+        self.oldlocale = locale.setlocale(self.category, None)
+        locale.setlocale(self.category, self.locale)
+
+    def __exit__(self, *args):
+        if self.oldlocale is None:
+            return
+        locale.setlocale(self.category, self.oldlocale)
+
+
+def _getdefaultlocale():
+    category = _get_locale_messages_category()
+    _locale = locale.setlocale(category, None)
+    if _locale == 'C':
+        with _different_locale(''):
+            # The LC_MESSAGES locale does not seem to be configured:
+            # get the user preferred locale.
+            _locale = locale.setlocale(category, None)
+    lang = _locale.split('.')[0]
+    if len(lang) > 2 and lang[2] != '_':
+        lang = lang[:2]
+
+    from babel import Locale
+    from babel.core import UnknownLocaleError
+    try:
+        babel_locale = Locale.parse(lang)
+    except UnknownLocaleError:
+        babel_locale = Locale.parse('en')
+    return babel_locale
+
+
+LOCALE = _getdefaultlocale()
 
 EN = {}
 FR = {"B": "octets", "MB": "Mo", "kB": "ko", "GB": "Go", "TB": "To",
@@ -95,8 +138,8 @@
       "Shortcuts": "Raccourcis", "Save As": "Enregistrer sous",
       "Recent": "Récents", "Recently used": "Récemment utilisés"}
 LANGUAGES = {"fr": FR, "en": EN}
-if LANG[:2] == "fr":
-    TR = LANGUAGES["fr"]
+if LOCALE.language in LANGUAGES:
+    TR = LANGUAGES[LOCALE.language]
 else:
     TR = LANGUAGES["en"]
 
@@ -110,15 +153,15 @@ def _(text):
 
 
 def locale_date(date=None):
-    return format_date(date, 'short', locale=LANG)
+    return format_date(date, 'short', locale=LOCALE)
 
 
 def locale_datetime(date=None):
-    return format_datetime(date, 'EEEE HH:mm', locale=LANG)
+    return format_datetime(date, 'EEEE HH:mm', locale=LOCALE)
 
 
 def locale_number(nb):
-    return format_number(nb, locale=LANG)
+    return format_number(nb, locale=LOCALE)
 
 
 SIZES = [_("B"), _("kB"), _("MB"), _("GB"), _("TB")]
@@ -126,7 +169,7 @@ def locale_number(nb):
 # ---  locale settings for dates
 TODAY = locale_date()
 YEAR = datetime.now().year
-DAY = int(format_date(None, 'D', locale=LANG))
+DAY = int(format_date(None, 'D', locale=LOCALE))
 
 
 # ---  functions