diff --git a/src/common/bcp47.cpp b/src/common/bcp47.cpp
index 4eb330173..9ea74922d 100644
--- a/src/common/bcp47.cpp
+++ b/src/common/bcp47.cpp
@@ -786,68 +786,62 @@ language_c::find_best_match(std::vector<language_c> const &potential_matches)
 language_c &
 language_c::canonicalize_preferred_values() {
   auto &preferred_values = mtx::iana::language_subtag_registry::g_preferred_values;
-  auto idx               = std::find_if(preferred_values.begin(), preferred_values.end(),
-                                        [this](auto const &pair) {
-                                          return matches(pair.first);
-                                        });
 
-  if (idx == preferred_values.end())
-    return *this;
+  for (auto const &[match, preferred] : preferred_values) {
+    if (!matches(match))
+      continue;
 
-  // mxdebug(fmt::format("found one! I am {0} first is {1} second {2}\n", dump(), idx->first.dump(), idx->second.dump()));
+     if (!preferred.m_language.empty()) {
+       if (!match.m_language.empty())
+         m_language.clear();
 
-  auto const &[match, preferred] = *idx;
+       if (!match.m_extended_language_subtags.empty())
+         m_extended_language_subtags.clear();
 
-  if (!preferred.m_language.empty()) {
-    if (!match.m_language.empty())
-      m_language.clear();
+       if (!match.m_script.empty())
+         m_script.clear();
 
-    if (!match.m_extended_language_subtags.empty())
-      m_extended_language_subtags.clear();
+       if (!match.m_region.empty())
+         m_region.clear();
 
-    if (!match.m_script.empty())
-      m_script.clear();
+       if (!match.m_variants.empty())
+         m_variants.clear();
 
-    if (!match.m_region.empty())
-      m_region.clear();
+       if (!match.m_extensions.empty())
+         m_extensions.clear();
 
-    if (!match.m_variants.empty())
-      m_variants.clear();
+       if (!match.m_private_use.empty())
+         m_private_use.clear();
 
-    if (!match.m_extensions.empty())
-      m_extensions.clear();
+       if (!match.m_grandfathered.empty())
+         m_grandfathered.clear();
+     }
 
-    if (!match.m_private_use.empty())
-      m_private_use.clear();
+     if (!preferred.m_language.empty())
+       m_language = preferred.m_language;
 
-    if (!match.m_grandfathered.empty())
-      m_grandfathered.clear();
+     if (!preferred.m_extended_language_subtags.empty())
+       m_extended_language_subtags = preferred.m_extended_language_subtags;
+
+     if (!preferred.m_script.empty())
+       m_script = preferred.m_script;
+
+     if (!preferred.m_region.empty())
+       m_region = preferred.m_region;
+
+     if (!preferred.m_variants.empty())
+       m_variants = preferred.m_variants;
+
+     if (!preferred.m_extensions.empty())
+       m_extensions = preferred.m_extensions;
+
+     if (!preferred.m_private_use.empty())
+       m_private_use = preferred.m_private_use;
+
+     if (!preferred.m_grandfathered.empty())
+       m_grandfathered = preferred.m_grandfathered;
   }
 
-  if (!preferred.m_language.empty())
-    m_language = preferred.m_language;
-
-  if (!preferred.m_extended_language_subtags.empty())
-    m_extended_language_subtags = preferred.m_extended_language_subtags;
-
-  if (!preferred.m_script.empty())
-    m_script = preferred.m_script;
-
-  if (!preferred.m_region.empty())
-    m_region = preferred.m_region;
-
-  if (!preferred.m_variants.empty())
-    m_variants = preferred.m_variants;
-
-  if (!preferred.m_extensions.empty())
-    m_extensions = preferred.m_extensions;
-
-  if (!preferred.m_private_use.empty())
-    m_private_use = preferred.m_private_use;
-
-  if (!preferred.m_grandfathered.empty())
-    m_grandfathered = preferred.m_grandfathered;
-
   return *this;
 }
 
diff --git a/tests/unit/common/bcp47.cpp b/tests/unit/common/bcp47.cpp
index 946cffbdc..19f382a43 100644
--- a/tests/unit/common/bcp47.cpp
+++ b/tests/unit/common/bcp47.cpp
@@ -448,6 +448,8 @@ TEST(BCP47LanguageTags, ToCanonicalForm) {
   EXPECT_EQ("hak"s,             language_c::parse("zh-hakka"s).to_canonical_form().format());
   EXPECT_EQ("hak"s,             language_c::parse("i-hak"s).to_canonical_form().format());
   EXPECT_EQ("yue-jyutping"s,    language_c::parse("zh-yue-jyutping"s).to_canonical_form().format());
+  EXPECT_EQ("zh-MM"s,           language_c::parse("zh-BU"s).to_canonical_form().format());
+  EXPECT_EQ("cmn-MM"s,          language_c::parse("zh-cmn-BU"s).to_canonical_form().format());
 }
 
 }