diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 7f6de7c82..924af9fcf 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -12,6 +12,7 @@ ones are marked like "v1.0.0-fork".
 * New tools for documentation:
   * New JavaScript documentation with [JSDoc](https://jsdoc.app/)! You will find it under `docs/js/`.
   * Better PHP documentation using [phpDocumentor](https://phpdoc.org/). The new documentation is at `docs/php/`.
+* New constant `LWT_LANG_DEFS`, that replaces `$langDefs` (in `inc/langdefs.php`). Part of [#163](https://github.com/HugoFara/lwt/issues/163). 
 
 ## Changed
 
@@ -20,6 +21,7 @@ ones are marked like "v1.0.0-fork".
 ### Deprecated
 
 * PHP documentation using Doxygen (under `/docs/html`) is now deprecated and will be removed in 3.0.0.
+* Using `$langDefs` is deprecated in favor of `LWT_LANG_DEFS` ([#163](https://github.com/HugoFara/lwt/issues/163)).
 
 ## 2.9.0-fork (December 24 2023)
 
diff --git a/docs/info.html b/docs/info.html
index a53bb6660..b9d515174 100644
--- a/docs/info.html
+++ b/docs/info.html
@@ -2175,6 +2175,7 @@ <h4>Added</h4>
 <li>Better PHP documentation using <a href="https://phpdoc.org/">phpDocumentor</a>. The new documentation is at <code>docs/php/</code>.</li>
 </ul>
 </li>
+<li>New constant <code>LWT_LANG_DEFS</code>, that replaces <code>$langDefs</code> (in <code>inc/langdefs.php</code>). Part of <a href="https://github.com/HugoFara/lwt/issues/163">#163</a>.</li>
 </ul>
 <h3>Changed</h3>
 <ul>
@@ -2183,6 +2184,7 @@ <h3>Changed</h3>
 <h4>Deprecated</h4>
 <ul>
 <li>PHP documentation using Doxygen (under <code>/docs/html</code>) is now deprecated and will be removed in 3.0.0.</li>
+<li>Using <code>$langDefs</code> is deprecated in favor of <code>LWT_LANG_DEFS</code> (<a href="https://github.com/HugoFara/lwt/issues/163">#163</a>).</li>
 </ul>
 <h3>2.9.0-fork (December 24 2023)</h3>
 <h4>Added in 2.9.0-fork</h4>
diff --git a/inc/langdefs.php b/inc/langdefs.php
index 2a942ff68..7832ef9b3 100644
--- a/inc/langdefs.php
+++ b/inc/langdefs.php
@@ -8,253 +8,301 @@
  *
  * @package Lwt
  * @author LWT Project <lwt-project@hotmail.com>
+ * @since 2.9.1 Use LWT_LANG_DEFS instead of $langDefs
  */
 
 /**
- * @var array $langDefs Associative array for all the supported languages
+ * @var array LWT_LANG_DEFS Associative array for all the supported languages
  * 
  * "Name" => 
  *  ("glosbeIso", "googleIso", biggerFont, "wordCharRegExp",
  *  "sentSplRegExp", makeCharacterWord, removeSpaces, rightToLeft)
  */
-$langDefs = array(
+define(
+    'LWT_LANG_DEFS',
+    array(
+        "Afrikaans" => array(
+            "af", "af", false, 
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ",    
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Arabic" => array(
+            "ar", "ar", true,
+            "\\x{610}-\\x{614}\\x{621}-\\x{65F}" .
+            "\\x{671}-\\x{6D3}\\x{6DE}-\\x{6FF}", 
+            ".!?:;\\x{061B}\\x{061F}", 
+            false, false, true
+        ),
+        
+        "Belarusian" => array(
+            "be", "be", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Bulgarian" => array(
+            "bg", "bg", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Catalan" => array(
+            "ca", "ca", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Chinese (Simplified)" => array(
+            "zh", "zh-CN", true,
+            "\\x{4E00}-\\x{9FFF}\\x{F900}-\\x{FAFF}", 
+            ".!?:;。！？：；", 
+            true, true, false
+        ),
+        
+        "Chinese (Traditional)" => array(
+            "zh", "zh-TW", true,
+            "\\x{4E00}-\\x{9FFF}\\x{F900}-\\x{FAFF}" .
+            "\\x{3100}-\\x{312F}", 
+            ".!?:;。！？：；", 
+            true, true, false
+        ),
+        
+        "Croatian" => array(
+            "hr", "hr", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Czech" => array(
+            "cs", "cs", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Danish" => array(
+            "da", "da", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Dutch" => array(
+            "nl", "nl", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "English" => array(
+            "en", "en", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Esperanto" => array(
+            "eo", "eo", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Estonian" => array(
+            "et", "et", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Finnish" => array(
+            "fi", "fi", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "French" => array(
+            "fr", "fr", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "German" => array(
+            "de", "de", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Greek (Modern)" => array(
+            "el", "el", false,
+            "\x{0370}-\x{03FF}\x{1F00}-\x{1FFF}", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Hebrew" => array(
+            "he", "iw", true, 
+            "\\x{0590}-\\x{05FF}", 
+            ".!?:;", 
+            false, false, true
+        ),
+        
+        "Hungarian" => array(
+            "hu", "hu", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Italian" => array(
+            "it", "it", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Japanese" => array(
+            "ja", "ja", true,
+            "\\x{4E00}-\\x{9FFF}\\x{F900}-\\x{FAFF}\\x{3040}-\\x{30FF}\\x{31F0}-\\x{31FF}",
+            ".!?:;。！？：；", 
+            true, true, false
+        ),
+        
+        "Korean" => array(
+            "ko", "ko", true, 
+            "\\x{4E00}-\\x{9FFF}\\x{F900}-\\x{FAFF}\\x{1100}-\\x{11FF}" .
+            "\\x{3130}-\\x{318F}\\x{AC00}-\\x{D7A0}", 
+            ".!?:;。！？：；", 
+            false, false, false
+        ),
+        
+        "Latin" => array(
+            "la", "la", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Latvian" => array(
+            "lv", "lv", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Lithuanian" => array(
+            "lt", "lt", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Macedonian" => array(
+            "mk", "mk", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Norwegian Bokmål" => array(
+            "nb", "no", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Polish" => array(
+            "pl", "pl", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Portuguese" => array(
+            "pt", "pt", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Romanian" => array(
+            "ro", "ro", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Russian" => array(
+            "ru", "ru", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Serbian" => array(
+            "sr", "sr", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Slovak" => array(
+            "sk", "sk", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Spanish" => array(
+            "es", "es", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Swedish" => array(
+            "sv", "sv", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Thai" => array(
+            "th", "th", true,
+            "\\x{0E00}-\\x{0E7F}", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Turkish" => array(
+            "tr", "tr", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        ),
+        
+        "Ukrainian" => array(
+            "uk", "uk", false,
+            "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
+            ".!?:;", 
+            false, false, false
+        )
+    )
+);
 
-    "Afrikaans" => 
-        array("af", "af", false, 
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ",    
-        ".!?:;", 
-        false, false, false),
-    
-    "Arabic" => 
-        array("ar", "ar", true,
-        "\\x{610}-\\x{614}\\x{621}-\\x{65F}" .
-        "\\x{671}-\\x{6D3}\\x{6DE}-\\x{6FF}", 
-        ".!?:;\\x{061B}\\x{061F}", 
-        false, false, true),
-    
-    "Belarusian" => 
-        array("be", "be", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Bulgarian" => 
-        array("bg", "bg", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Catalan" => 
-        array("ca", "ca", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Chinese (Simplified)" => 
-        array("zh", "zh-CN", true,
-        "\\x{4E00}-\\x{9FFF}\\x{F900}-\\x{FAFF}", 
-        ".!?:;。！？：；", 
-        true, true, false),
-    
-    "Chinese (Traditional)" => 
-        array("zh", "zh-TW", true,
-        "\\x{4E00}-\\x{9FFF}\\x{F900}-\\x{FAFF}" .
-        "\\x{3100}-\\x{312F}", 
-        ".!?:;。！？：；", 
-        true, true, false),
-    
-    "Croatian" => 
-        array("hr", "hr", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Czech" => 
-        array("cs", "cs", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Danish" => 
-        array("da", "da", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Dutch" => 
-        array("nl", "nl", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "English" => 
-        array("en", "en", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Esperanto" => 
-        array("eo", "eo", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Estonian" => 
-        array("et", "et", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Finnish" => 
-        array("fi", "fi", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "French" => 
-        array("fr", "fr", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "German" => 
-        array("de", "de", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Greek (Modern)" => 
-        array("el", "el", false,
-        "\x{0370}-\x{03FF}\x{1F00}-\x{1FFF}", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Hebrew" => 
-        array("he", "iw", true, 
-        "\\x{0590}-\\x{05FF}", 
-        ".!?:;", 
-        false, false, true),
-    
-    "Hungarian" => 
-        array("hu", "hu", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Italian" => 
-        array("it", "it", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Japanese" => 
-        array("ja", "ja", true,
-        "\\x{4E00}-\\x{9FFF}\\x{F900}-\\x{FAFF}\\x{3040}-\\x{30FF}\\x{31F0}-\\x{31FF}",
-        ".!?:;。！？：；", 
-        true, true, false),
-    
-    "Korean" => 
-        array("ko", "ko", true, 
-        "\\x{4E00}-\\x{9FFF}\\x{F900}-\\x{FAFF}\\x{1100}-\\x{11FF}" .
-        "\\x{3130}-\\x{318F}\\x{AC00}-\\x{D7A0}", 
-        ".!?:;。！？：；", 
-        false, false, false),
-    
-    "Latin" => 
-        array("la", "la", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Latvian" => 
-        array("lv", "lv", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Lithuanian" => 
-        array("lt", "lt", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Macedonian" => 
-        array("mk", "mk", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Norwegian Bokmål" => 
-        array("nb", "no", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Polish" => 
-        array("pl", "pl", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Portuguese" => 
-        array("pt", "pt", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Romanian" => 
-        array("ro", "ro", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Russian" => 
-        array("ru", "ru", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Serbian" => 
-        array("sr", "sr", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Slovak" => 
-        array("sk", "sk", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Spanish" => 
-        array("es", "es", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Swedish" => 
-        array("sv", "sv", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Thai" => 
-        array("th", "th", true,
-        "\\x{0E00}-\\x{0E7F}", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Turkish" => 
-        array("tr", "tr", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false),
-    
-    "Ukrainian" => 
-        array("uk", "uk", false,
-        "\\'a-zA-ZÀ-ÖØ-öø-ȳЀ-ӹ", 
-        ".!?:;", 
-        false, false, false)
-    
-    );
+/**
+ * @var array $langDefs Old name for LWT_LANG_DEFS.
+ * 
+ * @deprecated 2.9.1-fork, will be removed in 3.0.0
+ */
+$langDefs = LWT_LANG_DEFS;
 ?>