diff --git a/libretranslate/app.py b/libretranslate/app.py
index eb4fafe..beb5bb0 100644
--- a/libretranslate/app.py
+++ b/libretranslate/app.py
@@ -555,18 +555,14 @@ def create_app(args):
 
         if source_lang == "auto":
             candidate_langs = detect_languages(q if batch else [q])
-            source_langs = [candidate_langs[0]]
+            detected_src_lang = candidate_langs[0]
         else:
-            if batch:
-                source_langs = [ {"confidence": 100.0, "language": source_lang} for text in q]
-            else:
-                source_langs = [ {"confidence": 100.0, "language": source_lang} ]
+            detected_src_lang = {"confidence": 100.0, "language": source_lang}
 
-        src_langs = [next(iter([l for l in languages if l.code == source_lang["language"]]), None) for source_lang in source_langs]
+        src_lang = next(iter([l for l in languages if l.code == detected_src_lang["language"]]), None)
 
-        for idx, lang in enumerate(src_langs):
-            if lang is None:
-                abort(400, description=_("%(lang)s is not supported", lang=source_langs[idx]))
+        if src_lang is None:
+            abort(400, description=_("%(lang)s is not supported", lang=source_lang))
 
         tgt_lang = next(iter([l for l in languages if l.code == target_lang]), None)
 
@@ -582,10 +578,10 @@ def create_app(args):
         try:
             if batch:
                 results = []
-                for idx, text in enumerate(q):
-                    translator = src_langs[idx].get_translation(tgt_lang)
+                for _idx, text in enumerate(q):
+                    translator = src_lang.get_translation(tgt_lang)
                     if translator is None:
-                        abort(400, description=_("%(tname)s (%(tcode)s) is not available as a target language from %(sname)s (%(scode)s)", tname=_lazy(tgt_lang.name), tcode=tgt_lang.code, sname=_lazy(src_langs[idx].name), scode=src_langs[idx].code))
+                        abort(400, description=_("%(tname)s (%(tcode)s) is not available as a target language from %(sname)s (%(scode)s)", tname=_lazy(tgt_lang.name), tcode=tgt_lang.code, sname=_lazy(src_lang.name), scode=src_lang.code))
 
                     if text_format == "html":
                         translated_text = str(translate_html(translator, text))
@@ -597,7 +593,7 @@ def create_app(args):
                     return jsonify(
                         {
                             "translatedText": results,
-                            "detectedLanguage": source_langs
+                            "detectedLanguage": [detected_src_lang] * len(q)
                         }
                     )
                 else:
@@ -607,9 +603,9 @@ def create_app(args):
                           }
                     )
             else:
-                translator = src_langs[0].get_translation(tgt_lang)
+                translator = src_lang.get_translation(tgt_lang)
                 if translator is None:
-                    abort(400, description=_("%(tname)s (%(tcode)s) is not available as a target language from %(sname)s (%(scode)s)", tname=_lazy(tgt_lang.name), tcode=tgt_lang.code, sname=_lazy(src_langs[0].name), scode=src_langs[0].code))
+                    abort(400, description=_("%(tname)s (%(tcode)s) is not available as a target language from %(sname)s (%(scode)s)", tname=_lazy(tgt_lang.name), tcode=tgt_lang.code, sname=_lazy(src_lang.name), scode=src_lang.code))
 
                 if text_format == "html":
                     translated_text = str(translate_html(translator, q))
@@ -620,7 +616,7 @@ def create_app(args):
                     return jsonify(
                         {
                             "translatedText": unescape(translated_text),
-                            "detectedLanguage": source_langs[0]
+                            "detectedLanguage": detected_src_lang
                         }
                     )
                 else: