diff --git a/include/IEventReceiver.h b/include/IEventReceiver.h
index eae9be49..ccd1450a 100644
--- a/include/IEventReceiver.h
+++ b/include/IEventReceiver.h
@@ -468,8 +468,8 @@ struct SJoystickInfo
 	u32 Axes;
 
 	//! An indication of whether the joystick has a POV hat.
-	/** A Windows device will identify the presence or absence or the POV hat.  A
-	 *  Linux device cannot, and will always return POV_HAT_UNKNOWN. */
+	/** A Windows device will identify the presence or absence of the POV hat.
+	 *  A Linux device cannot, and will always return POV_HAT_UNKNOWN. */
 	enum
 	{
 		//! A hat is definitely present.
diff --git a/include/SMaterial.h b/include/SMaterial.h
index b4626dbb..777e5cc8 100644
--- a/include/SMaterial.h
+++ b/include/SMaterial.h
@@ -250,7 +250,7 @@ namespace video
 	//! Fine-tuning for SMaterial.ZWriteFineControl
 	enum E_ZWRITE_FINE_CONTROL
 	{
-		//! Default. Only write zbuffer when When SMaterial::ZBuffer is true and SMaterial::isTransparent() returns false.
+		//! Default. Only write zbuffer when SMaterial::ZBuffer is true and SMaterial::isTransparent() returns false.
 		EZI_ONLY_NON_TRANSPARENT,
 		//! Writing will just be based on SMaterial::ZBuffer value, transparency is ignored.
 		//! Needed mostly for certain shader materials as SMaterial::isTransparent will always return false for those.
@@ -508,7 +508,7 @@ namespace video
 		//! Will this material be lighted? Default: true
 		bool Lighting:1;
 
-		//! Is the zbuffer writeable or is it read-only. Default: true.
+		//! Is the zbuffer writable or is it read-only. Default: true.
 		/** This flag is forced to false if the MaterialType is a
 		transparent type and the scene parameter
 		ALLOW_ZWRITE_ON_TRANSPARENT is not set. If you set this parameter
diff --git a/include/quaternion.h b/include/quaternion.h
index 1fcbb06b..e6cd14e2 100644
--- a/include/quaternion.h
+++ b/include/quaternion.h
@@ -163,7 +163,7 @@ class quaternion
 		quaternion& slerp(quaternion q1, quaternion q2,
 				f32 time, f32 threshold=.05f);
 
-		//! Create quaternion from rotation angle and rotation axis.
+		//! Set this quaternion to represent a rotation from angle and axis.
 		/** Axis must be unit length.
 		The quaternion representing the rotation is
 		q = cos(A/2)+sin(A/2)*(x*i+y*j+z*k).
@@ -354,7 +354,7 @@ inline matrix4 quaternion::getMatrix() const
 //! Faster method to create a rotation matrix, you should normalize the quaternion before!
 inline void quaternion::getMatrixFast( matrix4 &dest) const
 {
-	// TODO: 
+	// TODO:
 	// gpu quaternion skinning => fast Bones transform chain O_O YEAH!
 	// http://www.mrelusive.com/publications/papers/SIMD-From-Quaternion-to-Matrix-and-Back.pdf
 	dest[0] = 1.0f - 2.0f*Y*Y - 2.0f*Z*Z;