diff --git a/ovos_bus_client/session.py b/ovos_bus_client/session.py
index 7bf2baa..1305cc7 100644
--- a/ovos_bus_client/session.py
+++ b/ovos_bus_client/session.py
@@ -7,7 +7,7 @@
 from ovos_config.config import Configuration
 from ovos_config.locale import get_default_lang
 from ovos_utils.log import LOG, log_deprecation
-
+from ovos_utils.lang import standardize_lang_tag
 from ovos_bus_client.message import dig_for_message, Message
 
 
@@ -297,7 +297,7 @@ def __init__(self, session_id: str = None,
                                    Configuration().get("skills", {}).get("blacklisted_skills", []))
         self.blacklisted_intents = (blacklisted_intents or
                                     Configuration().get("intents", {}).get("blacklisted_intents", []))
-        self.lang = lang or get_default_lang()
+        self.lang = standardize_lang_tag(lang or get_default_lang())
         self.system_unit = system_unit or Configuration().get("system_unit", "metric")
         self.date_format = date_format or Configuration().get("date_format", "DMY")
         self.time_format = time_format or Configuration().get("time_format", "full")
diff --git a/ovos_bus_client/util/__init__.py b/ovos_bus_client/util/__init__.py
index 5316f83..a89aa8d 100644
--- a/ovos_bus_client/util/__init__.py
+++ b/ovos_bus_client/util/__init__.py
@@ -20,6 +20,7 @@
 from ovos_config.config import read_mycroft_config
 from ovos_config.locale import get_default_lang
 from ovos_utils.json_helper import merge_dict
+from ovos_utils.lang import standardize_lang_tag
 from ovos_bus_client import MessageBusClient
 from ovos_bus_client.message import dig_for_message, Message
 from ovos_bus_client.session import SessionManager
@@ -39,14 +40,14 @@ def get_message_lang(message=None):
     # old style lang param
     lang = message.data.get("lang") or message.context.get("lang")
     if lang:
-        return lang
+        return standardize_lang_tag(lang)
 
     # new style session lang
     if "session_id" in message.context or "session" in message.context:
         sess = SessionManager.get(message)
         return sess.lang
 
-    return get_default_lang()
+    return standardize_lang_tag(get_default_lang())
 
 
 def get_websocket(host, port, route='/', ssl=False, threaded=True):
diff --git a/requirements.txt b/requirements.txt
index 0e006b1..140b27e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 ovos-config>=0.0.12,<1.0.0
-ovos-utils>=0.0.38,<1.0.0
+ovos-utils>=0.3.5,<1.0.0
 websocket-client>=0.54.0
 pyee>=8.1.0, < 12.0.0
 orjson
diff --git a/test/unittests/test_message.py b/test/unittests/test_message.py
index a3b285a..423b257 100644
--- a/test/unittests/test_message.py
+++ b/test/unittests/test_message.py
@@ -162,16 +162,16 @@ def test_no_lang_in_message(self):
         """No lang in message should result in lang from active locale."""
         setup_locale("it-it")
         msg = Message('test msg', data={})
-        self.assertEqual(get_message_lang(msg), 'it-it')
+        self.assertEqual(get_message_lang(msg), 'it-IT')
         setup_locale("en-us")
-        self.assertEqual(get_message_lang(msg), 'en-us')
+        self.assertEqual(get_message_lang(msg), 'en-US')
 
     def test_lang_exists(self):
         """Message has a lang code in data, it should be used."""
         msg = Message('test msg', data={'lang': 'de-de'})
-        self.assertEqual(get_message_lang(msg), 'de-de')
-        msg = Message('test msg', data={'lang': 'sv-se'})
-        self.assertEqual(get_message_lang(msg), 'sv-se')
+        self.assertEqual(get_message_lang(msg), 'de-DE')
+        msg = Message('test msg', data={'lang': 'sv-SE'})
+        self.assertEqual(get_message_lang(msg), 'sv-SE')
 
 
 class TestCollectionMessage(unittest.TestCase):