diff --git a/hwpfilter/source/hutil.h b/hwpfilter/source/hutil.h
index 84660e03c61e..340493fcac8f 100644
--- a/hwpfilter/source/hutil.h
+++ b/hwpfilter/source/hutil.h
@@ -21,11 +21,11 @@
 
 #include "hbox.h"
 /**
- * Transfer number to roman character
+ * Transfer number to Roman numeral
  */
 void    num2roman(int num, char *buf);
 /**
- * Transfer 8bit string to 16bit string used internally in hwp
+ * Transfer 8-bit string to 16-bit string used internally in hwp
  */
 void    str2hstr(const char *c, hchar *i);
 
diff --git a/hwpfilter/source/hwpfile.h b/hwpfilter/source/hwpfile.h
index 126b7edf0fd8..5d1abe4410be 100644
--- a/hwpfilter/source/hwpfile.h
+++ b/hwpfilter/source/hwpfile.h
@@ -88,9 +88,9 @@ struct HWPColumnInfo{
  * f.ReadHwpFile( stream );
  * </pre>
  *
- * There are two way to read hwp information from stream, one is to read all at a time
- * to use @ref ReadhwpFile() method like above example, other is to read partial information
- * to use @ref Open(), @ref InfoRead(), @ref FontRead(), @ref StyleRead(), @ref ParaListRead(), @ref TagsRead(),
+ * There are two ways to read hwp information from stream, one is to read all at a time
+ * using @ref ReadHwpFile() method like the example above; the other is to read partial information
+ * using @ref Open(), @ref InfoRead(), @ref FontRead(), @ref StyleRead(), @ref ParaListRead(), @ref TagsRead(),
  *
  * @short HWP file management object
  */
@@ -114,7 +114,7 @@ class DLLEXPORT HWPFile
 
 /**
  * Say current state
- * @returns 0 if normal, otherwise error code. If it's  bigger than USER_ERROR_BIT, it is internally using error, otherwise it's system error which is able to get the message @ref strerror() method.
+ * @returns 0 if normal, otherwise error code. If it's bigger than USER_ERROR_BIT, it is an internal error, otherwise it's system error which is able to get the message @ref strerror() method.
  */
         int State( void ) const { return error_code;}
 /**
@@ -282,7 +282,7 @@ class DLLEXPORT HWPFile
         std::vector<std::unique_ptr<HWPColumnInfo>> columnlist;
         // paragraph list
         std::vector<std::unique_ptr<HWPPara>> plist;
-        // keep paragraph's that failed to load until
+        // keep paragraphs that failed to load until
         // import is complete to avoid dangling references
         // elsewhere
         std::vector<std::unique_ptr<HWPPara>> pfailedlist;
@@ -297,7 +297,7 @@ class DLLEXPORT HWPFile
         std::vector<HeaderFooter*> headerfooters;
         std::vector<ShowPageNum*> pagenumbers;
         std::vector<std::unique_ptr<Table>> tables;
-        //track the stack of HParas types we're currently importing
+        // track the stack of HPara types we're currently importing
         std::vector<unsigned char> element_import_stack;
 
 // for global document handling
diff --git a/hwpfilter/source/hwplib.h b/hwpfilter/source/hwplib.h
index d62266cc4e3c..dd1f4518a66e 100644
--- a/hwpfilter/source/hwplib.h
+++ b/hwpfilter/source/hwplib.h
@@ -31,7 +31,7 @@
 
 /* hwp96부터 hunit가 4byte가 되었다. */
 /**
- * size of hunit is 4 since hwp96 version
+ * size of hunit is 4 bytes since hwp96 version
  */
 typedef char16_t  hchar;
 typedef int     hunit;