diff --git a/src/NXP/Stemmer.php b/src/NXP/Stemmer.php
index 0188434..73b993c 100644
--- a/src/NXP/Stemmer.php
+++ b/src/NXP/Stemmer.php
@@ -93,7 +93,7 @@ class Stemmer
     public static function removeEndings(&$word, $regex, $region)
     {
         $prefix = mb_substr($word, 0, $region, 'UTF-8');
-        $ending = substr($word, strlen($prefix));
+        $ending = mb_substr($word, mb_strlen($prefix, 'UTF-8'), null, 'UTF-8');
         if (is_array($regex)) {
             if (preg_match('/.+[а|я]' . $regex[0] . '/ui', $ending)) {
                 $word = $prefix . preg_replace('/' . $regex[0] . '/ui', '', $ending);