diff --git a/I18N Commander/Processor/DeepL.cs b/I18N Commander/Processor/DeepL.cs
index 5ec72bd..451ac5c 100644
--- a/I18N Commander/Processor/DeepL.cs	
+++ b/I18N Commander/Processor/DeepL.cs	
@@ -55,11 +55,8 @@ public static class DeepL
             var sourceCultureIndex = await AppSettings.GetDeepLSourceCultureIndex();
             var sourceCulture = await AppSettings.GetCultureCode(sourceCultureIndex);
 
-            // In case of the source culture, we cannot specify the region, so we need to remove it:
-            sourceCulture = sourceCulture.Split('-')[0];
-
             using var deepl = new Translator(deepLAPIKey);
-            var translation = await deepl.TranslateTextAsync(text, sourceCulture, targetCulture);
+            var translation = await deepl.TranslateTextAsync(text, TransformSourceCulture(sourceCulture), TransformTargetCulture(targetCulture));
 
             return translation.Text;
         }
@@ -78,4 +75,78 @@ public static class DeepL
     }
     
     public static void ResetState() => DEEPL_NOT_AVAILABLE = false;
+
+    private static string TransformSourceCulture(string sourceCulture) => sourceCulture switch
+    {
+        ['b', 'g', ..] => "BG", // Bulgarian
+        ['c', 's', ..] => "CS", // Czech
+        ['d', 'a', ..] => "DA", // Danish
+        ['d', 'e', ..] => "DE", // German
+        ['e', 'l', ..] => "EL", // Greek
+        ['e', 'n', ..] => "EN", // English
+        ['e', 's', ..] => "ES", // Spanish
+        ['e', 't', ..] => "ET", // Estonian
+        ['f', 'i', ..] => "FI", // Finnish
+        ['f', 'r', ..] => "FR", // French
+        ['h', 'u', ..] => "HU", // Hungarian
+        ['i', 'd', ..] => "ID", // Indonesian
+        ['i', 't', ..] => "IT", // Italian
+        ['j', 'a', ..] => "JA", // Japanese
+        ['k', 'o', ..] => "KO", // Korean
+        ['l', 't', ..] => "LT", // Lithuanian
+        ['l', 'v', ..] => "LV", // Latvian
+        ['n', 'b', ..] => "NB", // Norwegian
+        ['n', 'l', ..] => "NL", // Dutch
+        ['p', 'l', ..] => "PL", // Polish
+        ['p', 't', ..] => "PT", // Portuguese
+        ['r', 'o', ..] => "RO", // Romanian
+        ['r', 'u', ..] => "RU", // Russian
+        ['s', 'k', ..] => "SK", // Slovak
+        ['s', 'l', ..] => "SL", // Slovenian
+        ['s', 'v', ..] => "SV", // Swedish
+        ['t', 'r', ..] => "TR", // Turkish
+        ['u', 'k', ..] => "UK", // Ukrainian
+        ['z', 'h', ..] => "ZH", // Chinese
+
+        _ => sourceCulture,
+    };
+
+    private static string TransformTargetCulture(string targetCulture) => targetCulture switch
+    {
+        ['b', 'g', ..] => "BG", // Bulgarian
+        ['c', 's', ..] => "CS", // Czech
+        ['d', 'a', ..] => "DA", // Danish
+        ['d', 'e', ..] => "DE", // German
+        ['e', 'l', ..] => "EL", // Greek
+        ['e', 'n', '-', 'G', 'B', ..] => "EN-GB", // English (British)
+        ['e', 'n', '-', 'U', 'S', ..] => "EN-US", // English (American)
+        ['e', 'n', ..] => "EN-US", // English (American)
+        ['e', 's', ..] => "ES", // Spanish
+        ['e', 't', ..] => "ET", // Estonian
+        ['f', 'i', ..] => "FI", // Finnish
+        ['f', 'r', ..] => "FR", // French
+        ['h', 'u', ..] => "HU", // Hungarian
+        ['i', 'd', ..] => "ID", // Indonesian
+        ['i', 't', ..] => "IT", // Italian
+        ['j', 'a', ..] => "JA", // Japanese
+        ['k', 'o', ..] => "KO", // Korean
+        ['l', 't', ..] => "LT", // Lithuanian
+        ['l', 'v', ..] => "LV", // Latvian
+        ['n', 'b', ..] => "NB", // Norwegian
+        ['n', 'l', ..] => "NL", // Dutch
+        ['p', 'l', ..] => "PL", // Polish
+        ['p', 't', '-', 'B', 'R', ..] => "PT-BR", // Portuguese (Brazilian)
+        ['p', 't', '-', 'P', 'T', ..] => "PT-PT", // Portuguese (European)
+        ['p', 't', ..] => "PT-PT", // Portuguese (European)
+        ['r', 'o', ..] => "RO", // Romanian
+        ['r', 'u', ..] => "RU", // Russian
+        ['s', 'k', ..] => "SK", // Slovak
+        ['s', 'l', ..] => "SL", // Slovenian
+        ['s', 'v', ..] => "SV", // Swedish
+        ['t', 'r', ..] => "TR", // Turkish
+        ['u', 'k', ..] => "UK", // Ukrainian
+        ['z', 'h', ..] => "ZH", // Chinese
+        
+        _ => targetCulture,
+    };
 }
\ No newline at end of file
diff --git a/I18N Commander/Processor/Version.cs b/I18N Commander/Processor/Version.cs
index ce0516e..6cd05d2 100644
--- a/I18N Commander/Processor/Version.cs	
+++ b/I18N Commander/Processor/Version.cs	
@@ -2,5 +2,5 @@
 
 public static class Version
 {
-    public static string Text => $"v0.9.3 (2023-02-12), .NET {Environment.Version}";
+    public static string Text => $"v0.9.4 (2023-02-12), .NET {Environment.Version}";
 }
\ No newline at end of file