diff --git a/analysis_options.yaml b/analysis_options.yaml
index 8cccf3e..9f8939f 100644
--- a/analysis_options.yaml
+++ b/analysis_options.yaml
@@ -2,4 +2,8 @@ include: package:very_good_analysis/analysis_options.yaml
 
 analyzer:
   exclude: 
-    - example/*
\ No newline at end of file
+    - example/*
+
+linter:
+  rules:
+    use_late_for_private_fields_and_variables: false
diff --git a/lib/src/extensions.dart b/lib/src/extensions.dart
index 3c589fa..ed5bd3d 100644
--- a/lib/src/extensions.dart
+++ b/lib/src/extensions.dart
@@ -2,6 +2,7 @@ import 'package:any_date/any_date.dart';
 import 'package:meta/meta.dart';
 
 /// a collection of extensions on [DateTime]
+@internal
 extension DateTimeExtension on DateTime {
   /// returns a [DateTime] as UTC after applying the offset
   DateTime copyWithOffset(String offset) {
@@ -111,6 +112,8 @@ extension DateTimeExtension on DateTime {
       allowRollover: true,
     );
   }
+
+  DateTime get dateOnly => DateTime(year, month, day);
 }
 
 const _parser = AnyDate();
diff --git a/lib/src/param_cleanup_rules.dart b/lib/src/param_cleanup_rules.dart
index 9d52a48..15f4c17 100644
--- a/lib/src/param_cleanup_rules.dart
+++ b/lib/src/param_cleanup_rules.dart
@@ -84,7 +84,7 @@ const _knownSeparators = {..._usedSeparators, ..._specialSeparators};
 
 /// these are the separators used by the default DateTime.parse
 String _replaceSeparators(String formattedString, Iterable<String> separators) {
-  var result = formattedString;
+  var result = _replaceComma(formattedString);
   result = replaceUtc(result);
   final unknownSeparators = separators.toSet().difference(_knownSeparators);
 
@@ -97,6 +97,17 @@ String _replaceSeparators(String formattedString, Iterable<String> separators) {
   return _restoreMillisecons(result, separator).replaceAll(separator, '-');
 }
 
+String _replaceComma(String formattedString) {
+  final re1 = RegExp(r',\s+');
+  final re2 = RegExp(r',\s+');
+  final re3 = RegExp(r'\s+');
+
+  return formattedString
+      .replaceAll(re1, ' ')
+      .replaceAll(re2, ' ')
+      .replaceAll(re3, ' ');
+}
+
 String _restoreMillisecons(String formattedString, String separator) {
   // regex with T00:00:00-000
   final r = RegExp(
@@ -111,9 +122,19 @@ String _restoreMillisecons(String formattedString, String separator) {
   );
 }
 
+// .reversed because it works for disambiguation
+// (e.g., in vi locale try 'thang 12' before 'thang 1')
+Iterable<Month> _sortMonths(Iterable<Month> months) {
+  final sorted = months.toList()
+    ..sort((a, b) => a.name.length.compareTo(b.name.length))
+    ..sort((a, b) => a.number.compareTo(b.number));
+
+  return sorted.reversed;
+}
+
 Month? _expectMonth(DateParsingParameters parameters) {
   final timestamp = parameters.formattedString.toLowerCase();
-  final month = parameters.parserInfo.months.where(
+  final month = _sortMonths(parameters.parserInfo.months).where(
     (element) =>
         element.name.tryToInt() == null &&
         timestamp.contains(element.name.toLowerCase()),
@@ -125,12 +146,22 @@ Month? _expectMonth(DateParsingParameters parameters) {
   return month.firstOrNullExtension ?? english.firstOrNullExtension;
 }
 
+// .reversed because it works for disambiguation
+// (e.g., in vi locale try 'thang 12' before 'thang 1')
+Iterable<Weekday> _sortWeekdays(Iterable<Weekday> weekdays) {
+  final sorted = weekdays.toList()
+    ..sort((a, b) => a.name.length.compareTo(b.name.length))
+    ..sort((a, b) => a.number.compareTo(b.number));
+
+  return sorted.reversed;
+}
+
 Weekday? _expectWeekday(DateParsingParameters parameters) {
   // TODO(gbassisp): allow weekday in any part of the string
   // currently unsupported because some locales can have a conflict between
   // month and weekday (e.g., "Mar" in French for Mardi and Mars)
   final timestamp = parameters.formattedString.toLowerCase();
-  var weekday = parameters.parserInfo.weekdays
+  var weekday = _sortWeekdays(parameters.parserInfo.weekdays)
       .where(
         (element) => timestamp.startsWith(element.name.toLowerCase()),
         // (element) => timestamp
diff --git a/test/failing_locales_test.dart b/test/failing_locales_test.dart
new file mode 100644
index 0000000..49a78c8
--- /dev/null
+++ b/test/failing_locales_test.dart
@@ -0,0 +1,54 @@
+// the following locales are failing:
+// vi
+// nyn
+// ln
+// zh-TW
+// zh_HK
+// zh_CN
+// zh
+// ko
+// mn
+// ja
+import 'package:any_date/any_date.dart';
+import 'package:any_date/src/extensions.dart';
+import 'package:intl/intl.dart';
+import 'package:test/test.dart';
+
+import 'test_values.dart';
+
+const _failing = {
+  'vi',
+  'nyn',
+  'ln',
+  'zh_TW',
+  'zh_HK',
+  'zh_CN',
+  'zh',
+  'ko',
+  'mn',
+  'ja',
+};
+Future<void> main() async {
+  await initializeDateFormatting();
+
+  final date = DateTime.now().dateOnly;
+  group('ensure failing locales are working', () {
+    for (final l in _failing) {
+      final format = DateFormat.yMMMMd(l);
+      final formatted = format.format(date);
+      test('locale $l can parse $formatted text month', () {
+        final parser = AnyDate.fromLocale(l);
+
+        final parsed = parser.tryParse(formatted);
+
+        expect(parsed, equals(date));
+      });
+
+      test('sanity check - locale $l can self-parse $formatted text month', () {
+        final parsed = format.parse(formatted);
+
+        expect(parsed, equals(date));
+      });
+    }
+  });
+}