diff --git a/components/Tag/Tag.php b/components/Tag/Tag.php
index 9769b47812..83b475efad 100644
--- a/components/Tag/Tag.php
+++ b/components/Tag/Tag.php
@@ -97,10 +97,13 @@ class Tag extends Component
     public static function canonicalTag(string $tag, string $language): string
     {
         $result = '';
-        if (Event::handle('StemWord', [$language, $tag, &$result]) !== Event::stop) {
-            $result = Formatting::slugify($tag);
+        foreach (Formatting::splitWords(str_replace('#', '', $tag)) as $word) {
+            $temp_res = null;
+            if (Event::handle('StemWord', [$language, $word, &$temp_res]) !== Event::stop) {
+                $temp_res = $word;
+            }
+            $result .= Formatting::slugify($temp_res);
         }
-        $result = str_replace('#', '', $result);
         return self::ensureLength($result);
     }
 
diff --git a/plugins/StemWord/StemWord.php b/plugins/StemWord/StemWord.php
index 899e8ac529..b7a2c04565 100644
--- a/plugins/StemWord/StemWord.php
+++ b/plugins/StemWord/StemWord.php
@@ -29,7 +29,7 @@ use Wamania\Snowball\StemmerFactory;
 
 class StemWord extends Plugin
 {
-    public function onStemWord(string $language, string $word, string &$out)
+    public function onStemWord(string $language, string $word, ?string &$out)
     {
         $out = StemmerFactory::create($language)->stem($word);
         return Event::stop;
diff --git a/src/Util/Formatting.php b/src/Util/Formatting.php
index bb0b109801..fb2b8d29ee 100644
--- a/src/Util/Formatting.php
+++ b/src/Util/Formatting.php
@@ -267,13 +267,13 @@ abstract class Formatting
             $str = mb_convert_case($str, \MB_CASE_LOWER, 'UTF-8');
             return mb_substr($str, 0, $length);
         }
-        $str = transliterator_transliterate('Any-Latin;'                  // any charset to latin compatible
+        $str = transliterator_transliterate('Any-Latin;'                    // any charset to latin compatible
                                             . 'NFD;'                        // decompose
                                             . '[:Nonspacing Mark:] Remove;' // remove nonspacing marks (accents etc.)
                                             . 'NFC;'                        // composite again
                                             . '[:Punctuation:] Remove;'     // remove punctuation (.,¿? etc.)
                                             . 'Lower();'                    // turn into lowercase
-                                            . 'Latin-ASCII;',                 // get ASCII equivalents (ð to d for example)
+                                            . 'Latin-ASCII;',               // get ASCII equivalents (ð to d for example)
                                             $str, );
         return mb_substr(preg_replace('/[^\pL\pN]/u', '', $str), 0, $length);
     }
@@ -504,4 +504,12 @@ abstract class Formatting
 
         return $output;
     }
+
+    /**
+     * Split words by `-`, `_` or lower to upper case transitions
+     */
+    public static function splitWords(string $words): array
+    {
+        return preg_split('/-|_|(?<=\p{Ll})(?=\p{Lu})/u', $words);
+    }
 }