diff --git a/src/Carbon/CarbonInterface.php b/src/Carbon/CarbonInterface.php
index 6934279ac9..65acab0719 100644
--- a/src/Carbon/CarbonInterface.php
+++ b/src/Carbon/CarbonInterface.php
@@ -1622,6 +1622,9 @@ public function diffFiltered(CarbonInterval $ci, Closure $callback, $date = null
      *                                                            ` it can be the unit name (singular or plural) or its shortcut
      *                                                            ` (y, m, w, d, h, min, s, ms, µs).
      *                                                            - 'aUnit' entry, prefer "an hour" over "1 hour" if true
+     *                                                            - 'altNumbers' entry, use alternative numbers if available
+     *                                                              (from the current language if true is passed, from the given language(s)
+     *                                                              if array or string is passed)
      *                                                            - 'join' entry determines how to join multiple parts of the string
      *                                                            `  - if $join is a string, it's used as a joiner glue
      *                                                            `  - if $join is a callable/closure, it get the list of string and should return a string
diff --git a/src/Carbon/CarbonInterval.php b/src/Carbon/CarbonInterval.php
index d6373e2432..e2564cd28f 100644
--- a/src/Carbon/CarbonInterval.php
+++ b/src/Carbon/CarbonInterval.php
@@ -1828,6 +1828,9 @@ public function getValuesSequence(): array
      *                           ` it can be the unit name (singular or plural) or its shortcut
      *                           ` (y, m, w, d, h, min, s, ms, µs).
      *                           - 'aUnit' entry, prefer "an hour" over "1 hour" if true
+     *                           - 'altNumbers' entry, use alternative numbers if available
+     *                             (from the current language if true is passed, from the given language(s)
+     *                             if array or string is passed)
      *                           - 'join' entry determines how to join multiple parts of the string
      *                           `  - if $join is a string, it's used as a joiner glue
      *                           `  - if $join is a callable/closure, it get the list of string and should return a string
diff --git a/src/Carbon/Traits/Difference.php b/src/Carbon/Traits/Difference.php
index 310607eb49..b7aa6622cc 100644
--- a/src/Carbon/Traits/Difference.php
+++ b/src/Carbon/Traits/Difference.php
@@ -489,6 +489,9 @@ public function secondsUntilEndOfDay(): float
      *                                                            ` it can be the unit name (singular or plural) or its shortcut
      *                                                            ` (y, m, w, d, h, min, s, ms, µs).
      *                                                            - 'aUnit' entry, prefer "an hour" over "1 hour" if true
+     *                                                            - 'altNumbers' entry, use alternative numbers if available
+     *                                                              (from the current language if true is passed, from the given language(s)
+     *                                                              if array or string is passed)
      *                                                            - 'join' entry determines how to join multiple parts of the string
      *                                                            `  - if $join is a string, it's used as a joiner glue
      *                                                            `  - if $join is a callable/closure, it get the list of string and should return a string
diff --git a/tests/CarbonInterval/ConstructTest.php b/tests/CarbonInterval/ConstructTest.php
index 1f03af6945..f976f13190 100644
--- a/tests/CarbonInterval/ConstructTest.php
+++ b/tests/CarbonInterval/ConstructTest.php
@@ -435,18 +435,34 @@ public function testFromSerialization()
         $past = new Carbon('-3 Days');
         $today = new Carbon('today');
         $interval = $today->diffAsCarbonInterval($past);
+        /** @var CarbonInterval $copy */
         $copy =  unserialize(serialize($interval));
 
+        $this->assertInstanceOf(CarbonInterval::class, $copy);
+
+        $this->assertSame('2 days', $interval->forHumans(parts: 1));
+        $this->assertSame('2 days', $copy->forHumans(parts: 1));
+
         $this->assertSame(['en'], array_keys($interval->getLocalTranslator()->getMessages()) ?: ['en']);
         $this->assertSame(['en'], array_keys($copy->getLocalTranslator()->getMessages()) ?: ['en']);
+        $this->assertSame($interval->locale, $copy->locale);
+
+        // Ignore translator for the English comparison
+        $copy->setLocalTranslator($interval->getLocalTranslator());
 
-        $this->assertEquals($interval->locale('en'), $copy);
+        $this->assertEquals($interval, $copy);
 
-        $interval = $today->locale('zh')->diffAsCarbonInterval($past);
+        $interval = $today->locale('ja')->diffAsCarbonInterval($past);
+        /** @var CarbonInterval $copy */
         $copy =  unserialize(serialize($interval));
 
-        $this->assertSame(['zh'], array_keys($interval->getLocalTranslator()->getMessages()) ?: ['en']);
-        $this->assertSame(['zh'], array_keys($copy->getLocalTranslator()->getMessages()) ?: ['en']);
+        $this->assertInstanceOf(CarbonInterval::class, $copy);
+
+        $this->assertSame('二日', $interval->forHumans(['altNumbers' => true, 'parts' => 1]));
+        $this->assertSame('二日', $copy->forHumans(['altNumbers' => true, 'parts' => 1]));
+
+        $this->assertSame(['ja'], array_keys($interval->getLocalTranslator()->getMessages()));
+        $this->assertSame(['ja'], array_keys($copy->getLocalTranslator()->getMessages()));
 
         $this->assertEquals($interval, $copy);
     }