[demo] support English

app.py

@@ -36,16 +36,17 @@ def recognition(audio, lang='CN'):
             del decoder
             decoder = wenet.Decoder(lang='chs')
             cur_lang = 'CN'
+        ans = decoder.decode(y.tobytes(), True)
     elif lang == 'EN':
         if cur_lang != lang:
             del decoder
             decoder = wenet.Decoder(lang='en')
             cur_lang = 'EN'
-        # ans = decoder_en.decode(y.tobytes(), True)
+        ans = decoder.decode(y.tobytes(), True)
         return "ERROR! English is not supported yet!"
     else:
         return "ERROR! Please select a language!"
-    ans = decoder.decode(y.tobytes(), True)
+    
     if ans is None:
         return "ERROR! No text output! Please try again!"
     # NOTE: ans (json)