diff --git a/src/srtify/core/models.py b/src/srtify/core/models.py
index 0878995..cf0bbf9 100644
--- a/src/srtify/core/models.py
+++ b/src/srtify/core/models.py
@@ -43,7 +43,7 @@ class DirectoryConfig:
 @dataclass
 class TranslationConfig:
     """Translation configuration settings."""
-    default_language: str = "persian"
+    default_language: str = "Persian"
     batch_size: int = 300
 
     def __post_init__(self):
diff --git a/src/srtify/core/translator.py b/src/srtify/core/translator.py
index a47ac42..f48f2f9 100644
--- a/src/srtify/core/translator.py
+++ b/src/srtify/core/translator.py
@@ -42,7 +42,7 @@ class TranslatorApp:
 
         # Configure gemini_srt_translator
         gst.gemini_api_key = api_key
-        gst.target_language = language
+        gst.target_language = language.lower()
         gst.input_file = str(input_file)
         gst.output_file = str(output_file)
         gst.batch_size = batch_size