diff --git a/src/speaker/speaker.c b/src/speaker/speaker.c
index 744d054b..bd792c6d 100644
--- a/src/speaker/speaker.c
+++ b/src/speaker/speaker.c
@@ -84,6 +84,7 @@ static speaker_context _common_init()
     return dev;
 }
 
+// initialization in GPIO mode
 speaker_context speaker_init(int pin)
 {
     speaker_context dev = NULL;
@@ -109,7 +110,7 @@ speaker_context speaker_init(int pin)
     return dev;
 }
 
-// initialization of PWM uasage
+// initialization in PWM mode
 speaker_context speaker_init_pwm(int pin)
 {
     speaker_context dev = NULL;
diff --git a/src/speaker/speaker.hpp b/src/speaker/speaker.hpp
index 7da5ff52..71115ce8 100644
--- a/src/speaker/speaker.hpp
+++ b/src/speaker/speaker.hpp
@@ -130,7 +130,6 @@ namespace upm {
          * with setFrequency() or emit().  This function only operates
          * when in PWM mode.
          *
-         * @param dev Device context
          */
         void on();
 
@@ -138,7 +137,6 @@ namespace upm {
          * Turn the speaker off.  This function only operates when in
          * PWM mode.
          *
-         * @param dev Device context
          */
         void off();