diff --git a/backend/oasst_backend/config.py b/backend/oasst_backend/config.py
index 27b46bf5..da89d4d4 100644
--- a/backend/oasst_backend/config.py
+++ b/backend/oasst_backend/config.py
@@ -57,8 +57,8 @@ class TreeManagerConfiguration(BaseModel):
 
     labels_initial_prompt: list[TextLabel] = [
         TextLabel.spam,
+        TextLabel.lang_mismatch,
         TextLabel.quality,
-        TextLabel.helpfulness,
         TextLabel.creativity,
         TextLabel.humor,
         TextLabel.toxicity,
@@ -71,6 +71,7 @@ class TreeManagerConfiguration(BaseModel):
 
     labels_assistant_reply: list[TextLabel] = [
         TextLabel.spam,
+        TextLabel.lang_mismatch,
         TextLabel.fails_task,
         TextLabel.quality,
         TextLabel.helpfulness,
@@ -86,8 +87,8 @@ class TreeManagerConfiguration(BaseModel):
 
     labels_prompter_reply: list[TextLabel] = [
         TextLabel.spam,
+        TextLabel.lang_mismatch,
         TextLabel.quality,
-        TextLabel.helpfulness,
         TextLabel.humor,
         TextLabel.creativity,
         TextLabel.toxicity,
diff --git a/backend/oasst_backend/tree_manager.py b/backend/oasst_backend/tree_manager.py
index 145ca185..b8466ff0 100644
--- a/backend/oasst_backend/tree_manager.py
+++ b/backend/oasst_backend/tree_manager.py
@@ -376,6 +376,8 @@ class TreeManager:
                             label_mode = protocol_schema.LabelTaskMode.simple
                             label_disposition = protocol_schema.LabelTaskDisposition.spam
                             valid_labels = list(self.cfg.mandatory_labels_assistant_reply)
+                            if protocol_schema.TextLabel.lang_mismatch not in valid_labels:
+                                valid_labels.append(protocol_schema.TextLabel.lang_mismatch)
                             if protocol_schema.TextLabel.quality not in valid_labels:
                                 valid_labels.append(protocol_schema.TextLabel.quality)
 
@@ -400,6 +402,8 @@ class TreeManager:
                             label_mode = protocol_schema.LabelTaskMode.simple
                             label_disposition = protocol_schema.LabelTaskDisposition.spam
                             valid_labels = list(self.cfg.mandatory_labels_prompter_reply)
+                            if protocol_schema.TextLabel.lang_mismatch not in valid_labels:
+                                valid_labels.append(protocol_schema.TextLabel.lang_mismatch)
                             if protocol_schema.TextLabel.quality not in valid_labels:
                                 valid_labels.append(protocol_schema.TextLabel.quality)
 
@@ -483,6 +487,8 @@ class TreeManager:
                     valid_labels = self.cfg.mandatory_labels_initial_prompt
                     label_mode = protocol_schema.LabelTaskMode.simple
                     label_disposition = protocol_schema.LabelTaskDisposition.spam
+                    if protocol_schema.TextLabel.lang_mismatch not in valid_labels:
+                        valid_labels.append(protocol_schema.TextLabel.lang_mismatch)
 
                 logger.info(f"Generating a LabelInitialPromptTask ({label_mode=:s}).")
                 task = protocol_schema.LabelInitialPromptTask(
@@ -803,8 +809,12 @@ class TreeManager:
                 return backlog_tree
 
     def _calculate_acceptance(self, labels: list[TextLabels]):
-        # calculate acceptance based on spam label
-        return np.mean([1 - l.labels[protocol_schema.TextLabel.spam] for l in labels])
+        # calculate acceptance based on lang_mismatch & spam label
+        lang_mismatch = np.mean([(l.labels.get(protocol_schema.TextLabel.lang_mismatch) or 0) for l in labels])
+        spam = np.mean([l.labels[protocol_schema.TextLabel.spam] for l in labels])
+        acceptance_score = 1 - (spam + lang_mismatch)
+        logger.debug(f"{acceptance_score=} ({spam=}, {lang_mismatch=})")
+        return acceptance_score
 
     def _query_need_review(
         self, state: message_tree_state.State, required_reviews: int, root: bool, lang: str
diff --git a/oasst-shared/oasst_shared/schemas/protocol.py b/oasst-shared/oasst_shared/schemas/protocol.py
index 4cdea856..f69d254a 100644
--- a/oasst-shared/oasst_shared/schemas/protocol.py
+++ b/oasst-shared/oasst_shared/schemas/protocol.py
@@ -355,6 +355,12 @@ class TextLabel(str, enum.Enum):
     fails_task = "fails_task", LabelWidget.yes_no, "Fails to follow the correct instruction / task"
 
     # flags
+    lang_mismatch = (
+        "lang_mismatch",
+        LabelWidget.flag,
+        "Language mismatch",
+        "The message is written in language that differs from the currently selected language.",
+    )
     pii = "pii", LabelWidget.flag, "Contains personal identifiable information (PII)"
     not_appropriate = "not_appropriate", LabelWidget.flag, "Inappropriate"
     hate_speech = (
diff --git a/text-frontend/auto_main.py b/text-frontend/auto_main.py
index cea07c1e..c4ae19d3 100644
--- a/text-frontend/auto_main.py
+++ b/text-frontend/auto_main.py
@@ -96,9 +96,11 @@ def main(backend_url: str = "http://127.0.0.1:8080", api_key: str = "1234"):
                 else:
                     while labels_dict is None:
                         labels = random.sample(valid_labels, random.randint(1, len(valid_labels)))
-
                         if all([label in valid_labels for label in labels]):
-                            labels_dict = {label: "1" if label in labels else "0" for label in valid_labels}
+                            labels_dict = {
+                                label: 1 if label != "lang_mismatch" and label in labels else 0
+                                for label in valid_labels
+                            }
                         else:
                             invalid_labels = [label for label in labels if label not in valid_labels]
                             typer.echo(f"Invalid labels: {', '.join(invalid_labels)}. Valid: {', '.join(valid_labels)}")
@@ -212,9 +214,11 @@ def main(backend_url: str = "http://127.0.0.1:8080", api_key: str = "1234"):
                 else:
                     while labels_dict is None:
                         labels = random.sample(valid_labels, random.randint(1, len(valid_labels)))
-
                         if all([label in valid_labels for label in labels]):
-                            labels_dict = {label: "1" if label in labels else "0" for label in valid_labels}
+                            labels_dict = {
+                                label: 1 if label != "lang_mismatch" and label in labels else 0
+                                for label in valid_labels
+                            }
                         else:
                             invalid_labels = [label for label in labels if label not in valid_labels]
                             typer.echo(f"Invalid labels: {', '.join(invalid_labels)}. Valid: {', '.join(valid_labels)}")