diff --git a/types/dom-speech-recognition/dom-speech-recognition-tests.ts b/types/dom-speech-recognition/dom-speech-recognition-tests.ts
index cc874eb70f3153..10fc11a2e54bc7 100644
--- a/types/dom-speech-recognition/dom-speech-recognition-tests.ts
+++ b/types/dom-speech-recognition/dom-speech-recognition-tests.ts
@@ -94,4 +94,8 @@ const speechRecognitionOptions: SpeechRecognitionOptions = {
 (async () => {
     const availability: AvailabilityStatus = await SpeechRecognition.available(speechRecognitionOptions);
     const installOutcome: boolean = await SpeechRecognition.install(speechRecognitionOptions);
+
+    // "webkit" prefixed vars should have the same static methods
+    const webkitAvailability: AvailabilityStatus = await webkitSpeechRecognition.available(speechRecognitionOptions);
+    const webkitInstallOutcome: boolean = await webkitSpeechRecognition.install(speechRecognitionOptions);
 });
diff --git a/types/dom-speech-recognition/index.d.ts b/types/dom-speech-recognition/index.d.ts
index e2e0082ae4240b..bb7266c40d7dc8 100644
--- a/types/dom-speech-recognition/index.d.ts
+++ b/types/dom-speech-recognition/index.d.ts
@@ -146,7 +146,12 @@ declare var SpeechGrammarList: { prototype: SpeechGrammarList; new(): SpeechGram
 
 // prefixed global variables in Chrome; should match the equivalents above
 // https://developer.mozilla.org/en-US/docs/Web/API/Web_Speech_API/Using_the_Web_Speech_API#chrome_support
-declare var webkitSpeechRecognition: { prototype: SpeechRecognition; new(): SpeechRecognition };
+declare var webkitSpeechRecognition: {
+    prototype: SpeechRecognition;
+    new(): SpeechRecognition;
+    available(options: SpeechRecognitionOptions): Promise<AvailabilityStatus>;
+    install(options: SpeechRecognitionOptions): Promise<boolean>;
+};
 declare var webkitSpeechGrammarList: { prototype: SpeechGrammarList; new(): SpeechGrammarList };
 declare var webkitSpeechRecognitionEvent: {
     prototype: SpeechRecognitionEvent;
diff --git a/types/dom-speech-recognition/ts5.9/dom-speech-recognition-tests.ts b/types/dom-speech-recognition/ts5.9/dom-speech-recognition-tests.ts
index cc874eb70f3153..10fc11a2e54bc7 100644
--- a/types/dom-speech-recognition/ts5.9/dom-speech-recognition-tests.ts
+++ b/types/dom-speech-recognition/ts5.9/dom-speech-recognition-tests.ts
@@ -94,4 +94,8 @@ const speechRecognitionOptions: SpeechRecognitionOptions = {
 (async () => {
     const availability: AvailabilityStatus = await SpeechRecognition.available(speechRecognitionOptions);
     const installOutcome: boolean = await SpeechRecognition.install(speechRecognitionOptions);
+
+    // "webkit" prefixed vars should have the same static methods
+    const webkitAvailability: AvailabilityStatus = await webkitSpeechRecognition.available(speechRecognitionOptions);
+    const webkitInstallOutcome: boolean = await webkitSpeechRecognition.install(speechRecognitionOptions);
 });
diff --git a/types/dom-speech-recognition/ts5.9/index.d.ts b/types/dom-speech-recognition/ts5.9/index.d.ts
index 6b75d8b4748ca4..133e6c30aa3984 100644
--- a/types/dom-speech-recognition/ts5.9/index.d.ts
+++ b/types/dom-speech-recognition/ts5.9/index.d.ts
@@ -146,7 +146,12 @@ declare var SpeechGrammarList: { prototype: SpeechGrammarList; new(): SpeechGram
 
 // prefixed global variables in Chrome; should match the equivalents above
 // https://developer.mozilla.org/en-US/docs/Web/API/Web_Speech_API/Using_the_Web_Speech_API#chrome_support
-declare var webkitSpeechRecognition: { prototype: SpeechRecognition; new(): SpeechRecognition };
+declare var webkitSpeechRecognition: {
+    prototype: SpeechRecognition;
+    new(): SpeechRecognition;
+    available(options: SpeechRecognitionOptions): Promise<AvailabilityStatus>;
+    install(options: SpeechRecognitionOptions): Promise<boolean>;
+};
 declare var webkitSpeechGrammarList: { prototype: SpeechGrammarList; new(): SpeechGrammarList };
 declare var webkitSpeechRecognitionEvent: {
     prototype: SpeechRecognitionEvent;