diff --git a/src/ssvc/utils/namespace_patterns.py b/src/ssvc/utils/namespace_patterns.py
index eecfc57b..6d6d67ac 100644
--- a/src/ssvc/utils/namespace_patterns.py
+++ b/src/ssvc/utils/namespace_patterns.py
@@ -43,6 +43,5 @@
 )
 translation = f'\\.({reverse_dns}|{x_name})\\${bcp47}'
 ext_seg = f'({bcp47}|\\.{x_name}|{translation})'
-lang_ext = f'(/|/{bcp47})'
-extensions = f'{lang_ext}((/{ext_seg})+)?'
+extensions = f'(/{bcp47}(/{ext_seg})*|/(/{ext_seg})+)'
 namespace = f'{base_ns}({extensions})?'
diff --git a/src/ssvc/utils/ssvc_namespace_pattern.abnf b/src/ssvc/utils/ssvc_namespace_pattern.abnf
index 3a83807d..277ef95e 100644
--- a/src/ssvc/utils/ssvc_namespace_pattern.abnf
+++ b/src/ssvc/utils/ssvc_namespace_pattern.abnf
@@ -27,12 +27,10 @@ label = ALNUMLOW [ *61ALNUMLOWDASH ALNUMLOW ]
 
 fragment-seg = 1*ALNUMLOW *( SPECIALCHAR 1*ALNUMLOW )
 
-extensions = lang-ext [ 1*( "/" ext-seg ) ]
-
-; Language extension: either / (empty language extension)
-; or /<bcp47> (BCP-47 language code)
-
-lang-ext = "/" / ( "/" bcp47 )
+; Extension:
+;   either /<bcp47> (BCP-47 language code) optionally followed by ext-segs
+;   or / (empty language extension => default: en-US) followed by ext-segs
+extensions = ("/"  bcp47 *("/" ext-seg)) / ("/" 1*( "/" ext-seg ))
 
 ; Extension segment between slashes.
 ; - is either a language or
diff --git a/src/test/test_namespaces_pattern.py b/src/test/test_namespaces_pattern.py
index e0af0252..dfe14350 100644
--- a/src/test/test_namespaces_pattern.py
+++ b/src/test/test_namespaces_pattern.py
@@ -42,7 +42,6 @@ def setUp(self):
             "abc",  # not in enum, but valid for the pattern
             "ssvc#reference-arch-1",  # valid namespace with hash
             "x_example.test#test",
-            "x_example.test#test/",
             "x_example.test#test//.org.example#bar",
             "ssvc/de-DE/.org.example#reference-arch-1",  # valid BCP-47 tag, reverse domain notation, hash
             "ssvc//.de.bund.bsi$de-DE",  # BSI's translation of SSVC
@@ -81,6 +80,7 @@ def setUp(self):
             "ssvc$de-DE",  # official translations / base language are at the first extension level
             "anssi#800-30$fr-FR",  # official translations / base language are at the first extension level
             "x_gov.nist#800-30$de-DE",  # official translations / base language are at the first extension level
+            "ssvc/",  # empty language extension without extension segment; see #1233
             "ssvc/de-DE/example.organization##reference-arch-1",  # valid BCP-47 tag, reverse domain notation, double hash
             "ssvc/de-DE/example.organization#multi#hash#forbidden",  # valid BCP-47 tag, reverse domain notation, more than one hash per segment
             "x_custom.extension.",  # ends with punctuation