diff --git a/packages/captcha/src/audio.ts b/packages/captcha/src/audio.ts
index 42d9ae9..358f7ec 100644
--- a/packages/captcha/src/audio.ts
+++ b/packages/captcha/src/audio.ts
@@ -38,7 +38,7 @@ interface ReadableWritable extends ReadableProcess, WritableProcess {
 
 }
 
-export function espeak() {
+function espeak() {
   return run(
     'espeak',
     ['-k', '2', '-s', '90', '--stdin', '--stdout'],
diff --git a/packages/captcha/src/index.ts b/packages/captcha/src/index.ts
index 556dbfd..781c991 100644
--- a/packages/captcha/src/index.ts
+++ b/packages/captcha/src/index.ts
@@ -1 +1,2 @@
+export * from './audio'
 export * from './image'