diff --git a/audio.c b/audio.c
index 9079517..d263749 100644
--- a/audio.c
+++ b/audio.c
@@ -205,7 +205,7 @@ volatile bool     gFlagPlayQueuedVoice;
 VOICE_ID_t        gAnotherVoiceID = VOICE_ID_INVALID;
 
 
-void AUDIO_PlayVoice(uint8_t VoiceID)
+static void AUDIO_PlayVoice(uint8_t VoiceID)
 {
 	unsigned int i;
 
diff --git a/audio.h b/audio.h
index 19b5487..1e77675 100644
--- a/audio.h
+++ b/audio.h
@@ -149,7 +149,6 @@ static inline void AUDIO_AudioPathOff(void) {
 	extern volatile bool     gFlagPlayQueuedVoice;
 	extern VOICE_ID_t        gAnotherVoiceID;
 	
-	void    AUDIO_PlayVoice(uint8_t VoiceID);
 	void    AUDIO_PlaySingleVoice(bool bFlag);
 	void    AUDIO_SetVoiceID(uint8_t Index, VOICE_ID_t VoiceID);
 	uint8_t AUDIO_SetDigitVoice(uint8_t Index, uint16_t Value);
@@ -157,4 +156,3 @@ static inline void AUDIO_AudioPathOff(void) {
 #endif
 
 #endif
-