1 files changed, 3 insertions, 1 deletions
diff --git a/types/ext/language-descriptors.d.ts b/types/ext/language-descriptors.d.ts
index 856e55b3..778445de 100644
--- a/types/ext/language-descriptors.d.ts
+++ b/types/ext/language-descriptors.d.ts
@@ -174,7 +174,9 @@ type AllTextProcessors = {
         pre: CapitalizationPreprocessors;
     };
     vi: {
-        pre: CapitalizationPreprocessors;
+        pre: CapitalizationPreprocessors & {
+            normalizeDiacritics: TextProcessor<'old' | 'new' | 'off'>;
+        };
     };
     yue: Record<string, never>;
     zh: Record<string, never>;