diff --git a/pytorch_translate/generate.py b/pytorch_translate/generate.py
index c232f269..057f35dd 100644
--- a/pytorch_translate/generate.py
+++ b/pytorch_translate/generate.py
@@ -210,7 +210,10 @@ def _generate_score(models, args, task, dataset):
         for trans_info in _iter_translations(
             args, task, dataset, translations, align_dict, rescorer
         ):
-            scorer.add(trans_info.target_tokens, trans_info.hypo_tokens)
+            if hasattr(scorer, "add_string"):
+                scorer.add_string(trans_info.target_str, trans_info.hypo_str)
+            else:
+                scorer.add(trans_info.target_tokens, trans_info.hypo_tokens)
             if oracle_scorer is not None:
                 oracle_scorer.add(trans_info.target_tokens, trans_info.best_hypo_tokens)
             if rescoring_bleu_scorer is not None: