diff --git a/src/VoiceModuleTypes.ts b/src/VoiceModuleTypes.ts
index c1cb01e5..8081d9be 100644
--- a/src/VoiceModuleTypes.ts
+++ b/src/VoiceModuleTypes.ts
@@ -41,7 +41,7 @@ export type SpeechResultsEvent = {
 
 export type SpeechErrorEvent = {
   error?: {
-    code?: 'string';
+    code?: string;
     message?: string;
   };
 };