diff --git a/specification/cognitiveservices/data-plane/TextAnalytics/preview/v3.1-preview.4/TextAnalytics.json b/specification/cognitiveservices/data-plane/TextAnalytics/preview/v3.1-preview.4/TextAnalytics.json
index 00d1a1a0301c..e8c87e80ed8d 100644
--- a/specification/cognitiveservices/data-plane/TextAnalytics/preview/v3.1-preview.4/TextAnalytics.json
+++ b/specification/cognitiveservices/data-plane/TextAnalytics/preview/v3.1-preview.4/TextAnalytics.json
@@ -866,7 +866,7 @@
               "default": "latest",
               "type": "string"
             },
-            "piiCategories": {
+            "pii-categories": {
               "$ref": "#/definitions/PiiCategories"
             },
             "stringIndexType": {