Allow l11n type to reference the l11n.

Localization/BaseStringL11nType.php

@@ -40,6 +40,14 @@ class BaseStringL11nType implements \JsonSerializable
      */
     public string $title = '';
 
+    /*
+     * String l11n
+     *
+     * @var string | BaseStringL11n
+     * @since 1.0.0
+     */
+    public string | BaseStringL11n $l11n = '';
+
     /**
      * Is the l11n type required for an item?
      *
@@ -72,6 +80,44 @@ class BaseStringL11nType implements \JsonSerializable
         return $this->id;
     }
 
+    /**
+     * Set l11n
+     *
+     * @param string|BaseStringL11n $l11n Tag article l11n
+     * @param string                $lang Language
+     *
+     * @return void
+     *
+     * @since 1.0.0
+     */
+    public function setL11n(string | BaseStringL11n $l11n, string $lang = ISO639x1Enum::_EN) : void
+    {
+        if ($l11n instanceof BaseStringL11n) {
+            $this->l11n = $l11n;
+        } elseif (isset($this->l11n) && $this->l11n instanceof BaseStringL11n) {
+            $this->l11n->content = $l11n;
+            $this->l11n->setLanguage($lang);
+        } else {
+            $this->l11n          = new BaseStringL11n();
+            $this->l11n->content = $l11n;
+            $this->l11n->setLanguage($lang);
+        }
+    }
+
+    /**
+     * @return string
+     *
+     * @since 1.0.0
+     */
+    public function getL11n() : string
+    {
+        if (!isset($this->l11n)) {
+            return '';
+        }
+
+        return $this->l11n instanceof BaseStringL11n ? $this->l11n->content : $this->l11n;
+    }
+
     /**
      * {@inheritdoc}
      */