diff --git a/README.developer b/README.developer
index 835a30194..e986d81f8 100644
--- a/README.developer
+++ b/README.developer
@@ -158,7 +158,7 @@ http://www-cs-students.stanford.edu/~blynn/gitmagic/
 1.1.2 Providing patches with Git
 
 Git provides tools to generate patches and submit them to the Hamlib developers
-via email.  Use of these tools is prefered as Git allows credit to be given
+via email.  Use of these tools is preferred as Git allows credit to be given
 to the author and submitter of the patches.  Please submit the patches to
 the hamlib-developer mailing list.  See section 8.3.
 
diff --git a/include/hamlib/rig.h b/include/hamlib/rig.h
index be4959702..585eb1e76 100644
--- a/include/hamlib/rig.h
+++ b/include/hamlib/rig.h
@@ -82,7 +82,7 @@ extern HAMLIB_EXPORT_VAR(const char) hamlib_copyright[];
  * of rig_errcode_e definitions in case of error, or 0 when successful.
  */
 enum rig_errcode_e {
-	RIG_OK=0,		/*!< No error, operation completed sucessfully */
+	RIG_OK=0,		/*!< No error, operation completed successfully */
 	RIG_EINVAL,		/*!< invalid parameter */
 	RIG_ECONF,		/*!< invalid configuration (serial,..) */
 	RIG_ENOMEM,		/*!< memory shortage */
diff --git a/kit/funcube.c b/kit/funcube.c
index 50f7dd478..78dbf69cb 100644
--- a/kit/funcube.c
+++ b/kit/funcube.c
@@ -312,7 +312,7 @@ int get_freq_v0(RIG *rig, vfo_t vfo, freq_t *freq)
 {
 	struct funcube_priv_data *priv = (struct funcube_priv_data *)rig->state.priv;
 
-	rig_debug(RIG_DEBUG_TRACE, "%s: frequency is not read from the device, the value shown is the last succesfully set.\n",__func__);
+	rig_debug(RIG_DEBUG_TRACE, "%s: frequency is not read from the device, the value shown is the last successfully set.\n",__func__);
 	*freq = priv->freq;
 
 	return RIG_OK;
diff --git a/lib/termios.c b/lib/termios.c
index 5894a5aa8..acb043ff9 100644
--- a/lib/termios.c
+++ b/lib/termios.c
@@ -1220,7 +1220,7 @@ int win32_serial_open( const char *filename, int flags, ... )
 
 	if( check_port_capabilities( index ) )
 	{
-		report( "check_port_capabilites!" );
+		report( "check_port_capabilities!" );
 		win32_serial_close( index->fd );
 		return -1;
 	}
diff --git a/src/mem.c b/src/mem.c
index a357b0552..c4f24ef73 100644
--- a/src/mem.c
+++ b/src/mem.c
@@ -814,7 +814,7 @@ static int map_chan (RIG *rig, channel_t **chan, int channel_num, const chan_t *
  * \param arg	Arbitrary argument passed back to \a chan_cb
  *
  *  Write the data associated with a all the memory channels.
- *  This is the prefered method to support clonable rigs.
+ *  This is the preferred method to support clonable rigs.
  *
  * \return RIG_OK if the operation has been sucessful, otherwise
  * a negative value if an error occured (in which case, cause is
@@ -849,7 +849,7 @@ int HAMLIB_API rig_set_chan_all_cb (RIG *rig, chan_cb_t chan_cb, rig_ptr_t arg)
  * \param arg	Arbitrary argument passed back to \a chan_cb
  *
  *  Retrieves the data associated with a all the memory channels.
- *  This is the prefered method to support clonable rigs.
+ *  This is the preferred method to support clonable rigs.
  *
  *  \a chan_cb is called first with no data in chan (chan equals NULL).
  *  This means the application has to provide a struct where to store
@@ -1005,7 +1005,7 @@ int set_parm_all_cb_generic (RIG *rig, confval_cb_t parm_cb, rig_ptr_t cfgps,
  *
  * Writes the data associated with all the memory channels,
  * and rigs memory parameters, by callback.
- * This is the prefered method to support clonable rigs.
+ * This is the preferred method to support clonable rigs.
  *
  * \return RIG_OK if the operation has been sucessful, otherwise
  * a negative value if an error occured (in which case, cause is
@@ -1053,7 +1053,7 @@ int HAMLIB_API rig_set_mem_all_cb (RIG *rig, chan_cb_t chan_cb, confval_cb_t par
  *
  * Retrieves the data associated with all the memory channels,
  * and rigs memory parameters, by callback.
- * This is the prefered method to support clonable rigs.
+ * This is the preferred method to support clonable rigs.
  *
  * \return RIG_OK if the operation has been sucessful, otherwise
  * a negative value if an error occured (in which case, cause is
@@ -1156,7 +1156,7 @@ int HAMLIB_API rig_set_mem_all (RIG *rig, const channel_t chans[], const struct
  *
  * Retrieves the data associated with all the memory channels,
  * and rigs memory parameters.
- * This is the prefered method to support clonable rigs.
+ * This is the preferred method to support clonable rigs.
  *
  * \return RIG_OK if the operation has been sucessful, otherwise
  * a negative value if an error occured (in which case, cause is
diff --git a/src/rig.c b/src/rig.c
index 0e2dfc6a9..4fa5ff36a 100644
--- a/src/rig.c
+++ b/src/rig.c
@@ -142,7 +142,7 @@ static struct opened_rig_l *opened_rig_list = { NULL };
  * TODO: localise the messages..
  */
 static const char *rigerror_table[] = {
-	"Command completed sucessfully",
+	"Command completed successfully",
 	"Invalid parameter",
 	"Invalid configuration",
 	"Memory shortage",
diff --git a/tests/rigctld.8 b/tests/rigctld.8
index 543d74926..9bca774ed 100644
--- a/tests/rigctld.8
+++ b/tests/rigctld.8
@@ -592,7 +592,7 @@ And a \\set_mode command prepended with a '|' returns:
 .sp
 set_mode: USB 2400|RPRT 0
 .PP
-Such a format will allow reading a response as a single event using a prefered
+Such a format will allow reading a response as a single event using a preferred
 response separator.  Other punctuation characters have not been tested!
 .PP
 The following commands have been tested with the Extended Response protocol and
diff --git a/tests/rotctl.1 b/tests/rotctl.1
index 5c50773b0..f5327ea00 100644
--- a/tests/rotctl.1
+++ b/tests/rotctl.1
@@ -56,7 +56,7 @@ etc. on Win32.
 .TP
 .B \-s, --serial-speed=baud
 Set serial speed to \fIbaud\fP rate. Uses maximum serial speed from rotator
-backend capabilites as default.
+backend capabilities as default.
 .TP
 .B \-t, --send-cmd-term=char
 Change the termination \fIchar\fP for text protocol when using the
diff --git a/tests/rotctld.8 b/tests/rotctld.8
index 529fd7953..fe33764e5 100644
--- a/tests/rotctld.8
+++ b/tests/rotctld.8
@@ -399,7 +399,7 @@ And a \\set_pos command prepended with a '|' returns:
 .sp
 set_pos: 135 22.5|RPRT 0
 .PP
-Such a format will allow reading a response as a single event using a prefered
+Such a format will allow reading a response as a single event using a preferred
 response separator.  Other punctuation characters have not been tested!
 .PP
 All commands with the exception of \fI\\set_conf\fP have been tested with the
diff --git a/tests/testctld.pl b/tests/testctld.pl
index a18766d97..f488ff262 100755
--- a/tests/testctld.pl
+++ b/tests/testctld.pl
@@ -55,7 +55,7 @@ my $ret_val;
 
 # Error values returned from rigctld by Hamlib name
 my %errstr = (
-    RIG_OK          => "0",     # No error, operation completed sucessfully
+    RIG_OK          => "0",     # No error, operation completed successfully
     RIG_EINVAL      => "-1",    # invalid parameter
     RIG_ECONF       => "-2",    # invalid configuration (serial,..)
     RIG_ENOMEM      => "-3",    # memory shortage
diff --git a/tests/testrotctld.pl b/tests/testrotctld.pl
index 81322786d..2452dda07 100755
--- a/tests/testrotctld.pl
+++ b/tests/testrotctld.pl
@@ -54,7 +54,7 @@ my $ret_val;
 
 # Error values returned from rotctld by Hamlib name
 my %errstr = (
-    RIG_OK          => "0",     # No error, operation completed sucessfully
+    RIG_OK          => "0",     # No error, operation completed successfully
     RIG_EINVAL      => "-1",    # invalid parameter
     RIG_ECONF       => "-2",    # invalid configuration (serial,..)
     RIG_ENOMEM      => "-3",    # memory shortage