diff --git a/lib/Makefile.vxworks b/lib/Makefile.vxworks
index 796d1605ec37e7ee8dc46d1eaab4ab8f29859ac9..81a36cc0f96eb40db9915c58fdeea45ac7a5f1dc 100644
--- a/lib/Makefile.vxworks
+++ b/lib/Makefile.vxworks
@@ -5,7 +5,7 @@
 #Description: makefile to be used in order to compile libcurl for VxWoorks 6.3.
 #
 #How to use:
-#             1. Adjust environment variables at the file begining
+#             1. Adjust environment variables at the file beginning
 #             2. Open the Command Prompt window and change directory ('cd')
 #                into the 'lib' folder
 #             3. Add <CYGWIN>/bin folder to the PATH environment variable
diff --git a/lib/arpa_telnet.h b/lib/arpa_telnet.h
index ddb14f6fe58918c6b113e013adab6a58a9eae172..6626928b543e4344d8620957781ae052d05838e3 100644
--- a/lib/arpa_telnet.h
+++ b/lib/arpa_telnet.h
@@ -26,7 +26,7 @@
  * Telnet option defines. Add more here if in need.
  */
 #define CURL_TELOPT_BINARY   0  /* binary 8bit data */
-#define CURL_TELOPT_SGA      3  /* Supress Go Ahead */
+#define CURL_TELOPT_SGA      3  /* Suppress Go Ahead */
 #define CURL_TELOPT_EXOPL  255  /* EXtended OPtions List */
 #define CURL_TELOPT_TTYPE   24  /* Terminal TYPE */
 #define CURL_TELOPT_XDISPLOC 35 /* X DISPlay LOCation */
diff --git a/lib/axtls.c b/lib/axtls.c
index 892b8c3a57f71692a9b220c88da8331987fa9578..b6d93e90952beeb821c82e09ba921d5ed566f0d5 100644
--- a/lib/axtls.c
+++ b/lib/axtls.c
@@ -296,7 +296,7 @@ Curl_axtls_connect(struct connectdata *conn,
   else
     infof(data, "\t server certificate verification SKIPPED\n");
 
-  /* Here, gtls.c does issuer verfication. axTLS has no straightforward
+  /* Here, gtls.c does issuer verification. axTLS has no straightforward
    * equivalent, so omitting for now.*/
 
   /* See if common name was set in server certificate */
diff --git a/lib/connect.c b/lib/connect.c
index 3cde1805eb2d23106cf3d772d68886d39372f812..69d84c359e0f47dffe17ade67752d83307f89020 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -174,7 +174,7 @@ long Curl_timeleft(struct SessionHandle *data,
     nowp = &now;
   }
 
-  /* substract elapsed time */
+  /* subtract elapsed time */
   timeout_ms -= Curl_tvdiff(*nowp, data->progress.t_startsingle);
   if(!timeout_ms)
     /* avoid returning 0 as that means no timeout! */
diff --git a/lib/cookie.c b/lib/cookie.c
index 4140d94b8c5c9ce50f590b8b37cfa92b6ad5e7f0..e81b9e36e01716ed192188d5a9808245c895fc1b 100644
--- a/lib/cookie.c
+++ b/lib/cookie.c
@@ -266,7 +266,7 @@ Curl_cookie_add(struct SessionHandle *data,
             }
           }
           else if(Curl_raw_equal("domain", name)) {
-            /* note that this name may or may not have a preceeding dot, but
+            /* note that this name may or may not have a preceding dot, but
                we don't care about that, we treat the names the same anyway */
 
             const char *domptr=whatptr;
@@ -307,7 +307,7 @@ Curl_cookie_add(struct SessionHandle *data,
                  or the given domain is not valid and thus cannot be set. */
 
               if('.' == whatptr[0])
-                whatptr++; /* ignore preceeding dot */
+                whatptr++; /* ignore preceding dot */
 
               if(!domain || tailmatch(whatptr, domain)) {
                 const char *tailptr=whatptr;
@@ -479,7 +479,7 @@ Curl_cookie_add(struct SessionHandle *data,
        marked with httpOnly after the domain name are not accessible
        from javascripts, but since curl does not operate at javascript
        level, we include them anyway. In Firefox's cookie files, these
-       lines are preceeded with #HttpOnly_ and then everything is
+       lines are preceded with #HttpOnly_ and then everything is
        as usual, so we skip 10 characters of the line..
     */
     if (strncmp(lineptr, "#HttpOnly_", 10) == 0) {
@@ -514,7 +514,7 @@ Curl_cookie_add(struct SessionHandle *data,
         ptr=strtok_r(NULL, "\t", &tok_buf), fields++) {
       switch(fields) {
       case 0:
-        if(ptr[0]=='.') /* skip preceeding dots */
+        if(ptr[0]=='.') /* skip preceding dots */
           ptr++;
         co->domain = strdup(ptr);
         if(!co->domain)
diff --git a/lib/curl_sspi.h b/lib/curl_sspi.h
index 221bce128994aa2650fd0c1fa04c1b9188c66dc3..c0e4f368f1071b9897c39c5e4c50bfe176f0f39d 100644
--- a/lib/curl_sspi.h
+++ b/lib/curl_sspi.h
@@ -29,7 +29,7 @@
 #include <curl/curl.h>
 
 /*
- * When including the folowing three headers, it is mandatory to define either
+ * When including the following three headers, it is mandatory to define either
  * SECURITY_WIN32 or SECURITY_KERNEL, indicating who is compiling the code.
  */
 
diff --git a/lib/ftp.c b/lib/ftp.c
index d08ae3fff513438f7fd531979fd8e06b51cfaf4a..9be8ed997384e2bd6f5d18d665bd2e0840d7c840 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -2162,7 +2162,7 @@ static CURLcode ftp_state_get_resp(struct connectdata *conn,
     /*
       A;
       150 Opening BINARY mode data connection for /etc/passwd (2241
-      bytes).  (ok, the file is being transfered)
+      bytes).  (ok, the file is being transferred)
 
       B:
       150 Opening ASCII mode data connection for /bin/ls
@@ -2194,7 +2194,7 @@ static CURLcode ftp_state_get_resp(struct connectdata *conn,
       /*
        * It seems directory listings either don't show the size or very
        * often uses size 0 anyway. ASCII transfers may very well turn out
-       * that the transfered amount of data is not the same as this line
+       * that the transferred amount of data is not the same as this line
        * tells, why using this number in those cases only confuses us.
        *
        * Example D above makes this parsing a little tricky */
@@ -2692,7 +2692,7 @@ static CURLcode ftp_statemach_act(struct connectdata *conn)
     case FTP_RETR_PREQUOTE:
     case FTP_STOR_PREQUOTE:
       if((ftpcode >= 400) && !ftpc->count2) {
-        /* failure reponse code, and not allowed to fail */
+        /* failure response code, and not allowed to fail */
         failf(conn->data, "QUOT command failed with %03d", ftpcode);
         return CURLE_QUOTE_ERROR;
       }
@@ -2913,7 +2913,7 @@ static CURLcode ftp_connect(struct connectdata *conn,
   if(CURLE_OK != result)
     return result;
 
-  /* We always support persistant connections on ftp */
+  /* We always support persistent connections on ftp */
   conn->bits.close = FALSE;
 
   pp->response_time = RESP_TIMEOUT; /* set default response time-out */
@@ -3109,7 +3109,7 @@ static CURLcode ftp_done(struct connectdata *conn, CURLcode status,
     /*
      * Let's see what the server says about the transfer we just performed,
      * but lower the timeout as sometimes this connection has died while the
-     * data has been transfered. This happens when doing through NATs etc that
+     * data has been transferred. This happens when doing through NATs etc that
      * abandon old silent connections.
      */
     long old_time = pp->response_time;
@@ -3981,7 +3981,7 @@ CURLcode ftp_parse_url_path(struct connectdata *conn)
         /* seek out the next path component */
         if(slash_pos-cur_pos) {
           /* we skip empty path components, like "x//y" since the FTP command
-             CWD requires a parameter and a non-existant parameter a) doesn't
+             CWD requires a parameter and a non-existent parameter a) doesn't
              work on many servers and b) has no effect on the others. */
           int len = (int)(slash_pos - cur_pos + absolute_dir);
           ftpc->dirs[ftpc->dirdepth] =
diff --git a/lib/getinfo.c b/lib/getinfo.c
index 946686281979d8e90857658d379d1a0db128b03f..bb289741a70f05cb4ef87402ed3dfee06e5bacd2 100644
--- a/lib/getinfo.c
+++ b/lib/getinfo.c
@@ -260,7 +260,7 @@ CURLcode Curl_getinfo(struct SessionHandle *data, CURLINFO info, ...)
     *param_slistp = ptr.to_slist;
     break;
   case CURLINFO_CONDITION_UNMET:
-    /* return if the condition prevented the document to get transfered */
+    /* return if the condition prevented the document to get transferred */
     *param_longp = data->info.timecond;
     break;
   case CURLINFO_RTSP_SESSION_ID:
diff --git a/lib/hostip.h b/lib/hostip.h
index c1f4486a6b5bd0bdfc992cc3292673c566b3791b..a7c33456893611f5ab978df74a371f96ac133f61 100644
--- a/lib/hostip.h
+++ b/lib/hostip.h
@@ -186,7 +186,7 @@ Curl_addrinfo *Curl_ipv4_resolve_r(const char * hostname, int port);
  * Curl_addrinfo_callback() is used when we build with any asynch specialty.
  * Handles end of async request processing. Inserts ai into hostcache when
  * status is CURL_ASYNC_SUCCESS. Twiddles fields in conn to indicate async
- * request completed wether successfull or failed.
+ * request completed wether successful or failed.
  */
 CURLcode Curl_addrinfo_callback(struct connectdata *conn,
                                 int status,
diff --git a/lib/http_negotiate.c b/lib/http_negotiate.c
index 80b0b507d43efb5f87f9a37c16b7675744f29581..673f8c90844d36529eb9cebfad0c1a68ad931cb9 100644
--- a/lib/http_negotiate.c
+++ b/lib/http_negotiate.c
@@ -167,7 +167,7 @@ int Curl_input_negotiate(struct connectdata *conn, bool proxy,
   }
 
   if(neg_ctx->context && neg_ctx->status == GSS_S_COMPLETE) {
-    /* We finished succesfully our part of authentication, but server
+    /* We finished successfully our part of authentication, but server
      * rejected it (since we're again here). Exit with an error since we
      * can't invent anything better */
     Curl_cleanup_negotiate(conn->data);
diff --git a/lib/http_negotiate_sspi.c b/lib/http_negotiate_sspi.c
index 53459b68b2df7f832a9fc48299c2a9757013de35..5843ab25111a34dc63f143af85d18ef9c772e817 100644
--- a/lib/http_negotiate_sspi.c
+++ b/lib/http_negotiate_sspi.c
@@ -122,7 +122,7 @@ int Curl_input_negotiate(struct connectdata *conn, bool proxy,
   }
 
   if(neg_ctx->context && neg_ctx->status == SEC_E_OK) {
-    /* We finished succesfully our part of authentication, but server
+    /* We finished successfully our part of authentication, but server
      * rejected it (since we're again here). Exit with an error since we
      * can't invent anything better */
     Curl_cleanup_negotiate(conn->data);
@@ -165,7 +165,7 @@ int Curl_input_negotiate(struct connectdata *conn, bool proxy,
   }
 
   if ( !input_token ) {
-    /* first call in a new negotation, we have to require credentials,
+    /* first call in a new negotiation, we have to require credentials,
        and allocate memory for the context */
 
     neg_ctx->credentials = (CredHandle *)malloc(sizeof(CredHandle));
diff --git a/lib/imap.c b/lib/imap.c
index b6f807a4ba66670a11059a8d97afec9c5d2ac9ac..78c412e1389b0d690a6d176c2db43678e2229749 100644
--- a/lib/imap.c
+++ b/lib/imap.c
@@ -470,7 +470,7 @@ static CURLcode imap_state_fetch_resp(struct connectdata *conn,
     infof(data, "Filesize left: %" FORMAT_OFF_T "\n", filesize);
 
     if(!filesize)
-      /* the entire data is already transfered! */
+      /* the entire data is already transferred! */
       Curl_setup_transfer(conn, -1, -1, FALSE, NULL, -1, NULL);
     else
       /* IMAP download */
@@ -709,7 +709,7 @@ static CURLcode imap_connect(struct connectdata *conn,
   if(CURLE_OK != result)
     return result;
 
-  /* We always support persistant connections on imap */
+  /* We always support persistent connections on imap */
   conn->bits.close = FALSE;
 
   pp->response_time = RESP_TIMEOUT; /* set default response time-out */
diff --git a/lib/inet_ntop.c b/lib/inet_ntop.c
index 26867f4d26bc98c3a437cc44d354e1ff9feff50d..5012fbc4ca9d3508a83a45e939ecb7457632a46b 100644
--- a/lib/inet_ntop.c
+++ b/lib/inet_ntop.c
@@ -195,9 +195,9 @@ static char *inet_ntop6 (const unsigned char *src, char *dst, size_t size)
  * error, EAFNOSUPPORT or ENOSPC.
  *
  * On Windows we store the error in the thread errno, not
- * in the winsock error code. This is to avoid loosing the
+ * in the winsock error code. This is to avoid losing the
  * actual last winsock error. So use macro ERRNO to fetch the
- * errno this funtion sets when returning NULL, not SOCKERRNO.
+ * errno this function sets when returning NULL, not SOCKERRNO.
  */
 char *Curl_inet_ntop(int af, const void *src, char *buf, size_t size)
 {
diff --git a/lib/inet_pton.c b/lib/inet_pton.c
index 967e30fb117f8368f92e7889dd6384320b67765e..d2a54e9f3b515be18ead654ccbe0d761875b9c84 100644
--- a/lib/inet_pton.c
+++ b/lib/inet_pton.c
@@ -61,9 +61,9 @@ static int      inet_pton6(const char *src, unsigned char *dst);
  *      -1 if some other error occurred (`dst' is untouched in this case, too)
  * notice:
  *      On Windows we store the error in the thread errno, not
- *      in the winsock error code. This is to avoid loosing the
+ *      in the winsock error code. This is to avoid losing the
  *      actual last winsock error. So use macro ERRNO to fetch the
- *      errno this funtion sets when returning (-1), not SOCKERRNO.
+ *      errno this function sets when returning (-1), not SOCKERRNO.
  * author:
  *      Paul Vixie, 1996.
  */
diff --git a/lib/ldap.c b/lib/ldap.c
index 95e926f08364e42e05e5e5a6497d5a7abb640503..3f067230f9434af8e2f5ff198c65251201ce0fd7 100644
--- a/lib/ldap.c
+++ b/lib/ldap.c
@@ -218,7 +218,7 @@ static CURLcode Curl_ldap(struct connectdata *conn, bool *done)
   if(ldap_ssl) {
 #ifdef HAVE_LDAP_SSL
 #ifdef CURL_LDAP_WIN
-    /* Win32 LDAP SDK doesnt support insecure mode without CA! */
+    /* Win32 LDAP SDK doesn't support insecure mode without CA! */
     server = ldap_sslinit(conn->host.name, (int)conn->port, 1);
     ldap_set_option(server, LDAP_OPT_SSL, LDAP_OPT_ON);
 #else
diff --git a/lib/mprintf.c b/lib/mprintf.c
index 536c0c247cebfc6e1ba398eac98c27c265e4757b..b02b5025347a9efb69280604b8167ea6707dcd7a 100644
--- a/lib/mprintf.c
+++ b/lib/mprintf.c
@@ -124,7 +124,7 @@ typedef enum  {
   FORMAT_WIDTH /* For internal use */
 } FormatType;
 
-/* convertion and display flags */
+/* conversion and display flags */
 enum {
   FLAGS_NEW        = 0,
   FLAGS_SPACE      = 1<<0,
@@ -692,7 +692,7 @@ static int dprintf_formatf(
       continue;
     }
 
-    /* If this is a positional parameter, the position must follow imediately
+    /* If this is a positional parameter, the position must follow immediately
        after the %, thus create a %<num>$ sequence */
     param=dprintf_DollarString(f, &f);
 
diff --git a/lib/multi.c b/lib/multi.c
index f1c045b44d4f9f0935db6d5d5e34e5337a58800b..40a341d295c7980f3046933f8754d684d33d8f2d 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -645,7 +645,7 @@ CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
        easy->state > CURLM_STATE_WAITDO &&
        easy->state < CURLM_STATE_COMPLETED) {
       /* If the handle is in a pipeline and has started sending off its
-         request but not received its reponse yet, we need to close
+         request but not received its response yet, we need to close
          connection. */
       easy->easy_conn->bits.close = TRUE;
       /* Set connection owner so that Curl_done() closes it.
@@ -1495,7 +1495,7 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi,
         /* call this even if the readwrite function returned error */
         Curl_posttransfer(data);
 
-        /* we're no longer receving */
+        /* we're no longer receiving */
         moveHandleFromRecvToDonePipeline(data,
                                          easy->easy_conn);
 
diff --git a/lib/parsedate.c b/lib/parsedate.c
index 1e9381c7d1f69cba874ea851057da9661d07f01a..298481701ca08c468201ca17cd9b9f49cd7dc8a4 100644
--- a/lib/parsedate.c
+++ b/lib/parsedate.c
@@ -387,7 +387,7 @@ int Curl_parsedate(const char *date, time_t *output)
            (indate< date) &&
            ((date[-1] == '+' || date[-1] == '-'))) {
           /* four digits and a value less than or equal to 1400 (to take into
-             account all sorts of funny time zone diffs) and it is preceeded
+             account all sorts of funny time zone diffs) and it is preceded
              with a plus or minus. This is a time zone indication.  1400 is
              picked since +1300 is frequently used and +1400 is mentioned as
              an edge number in the document "ISO C 200X Proposal: Timezone
diff --git a/lib/pop3.c b/lib/pop3.c
index 8f37c1fe60aa4b9946f64bfe3583b24957c2978d..d0aba352b0267e5d696b349a8708df14bde9cbd6 100644
--- a/lib/pop3.c
+++ b/lib/pop3.c
@@ -641,7 +641,7 @@ static CURLcode pop3_connect(struct connectdata *conn,
   if(CURLE_OK != result)
     return result;
 
-  /* We always support persistant connections on pop3 */
+  /* We always support persistent connections on pop3 */
   conn->bits.close = FALSE;
 
   pp->response_time = RESP_TIMEOUT; /* set default response time-out */
diff --git a/lib/progress.c b/lib/progress.c
index 49047f1a67a35fb50ab6e44580d2618b77a90af6..e37c34d99053febc963ac9f72a26dbf4dc02ebc5 100644
--- a/lib/progress.c
+++ b/lib/progress.c
@@ -409,17 +409,17 @@ int Curl_pgrsUpdate(struct connectdata *conn)
     time2str(time_total, total_estimate);
     time2str(time_spent, timespent);
 
-    /* Get the total amount of data expected to get transfered */
+    /* Get the total amount of data expected to get transferred */
     total_expected_transfer =
       (data->progress.flags & PGRS_UL_SIZE_KNOWN?
        data->progress.size_ul:data->progress.uploaded)+
       (data->progress.flags & PGRS_DL_SIZE_KNOWN?
        data->progress.size_dl:data->progress.downloaded);
 
-    /* We have transfered this much so far */
+    /* We have transferred this much so far */
     total_transfer = data->progress.downloaded + data->progress.uploaded;
 
-    /* Get the percentage of data transfered so far */
+    /* Get the percentage of data transferred so far */
     if(total_expected_transfer > CURL_OFF_T_C(10000))
       total_percen = total_transfer /
         (total_expected_transfer/CURL_OFF_T_C(100));
diff --git a/lib/qssl.c b/lib/qssl.c
index e56a651e5cc05183267d9dff5a2c89383d45eaf3..55031491ef64c05eb4e3ca2d7809d521fa281064 100644
--- a/lib/qssl.c
+++ b/lib/qssl.c
@@ -395,7 +395,7 @@ static ssize_t qsossl_send(struct connectdata * conn, int sockindex,
 
     case SSL_ERROR_BAD_STATE:
       /* The operation did not complete; the same SSL I/O function
-         should be called again later. This is basicly an EWOULDBLOCK
+         should be called again later. This is basically an EWOULDBLOCK
          equivalent. */
       *curlcode = CURLE_AGAIN;
       return -1;
diff --git a/lib/security.c b/lib/security.c
index 1aa280682c7c0eadf7ab92a350b00917e0e7400b..c4fc88af898333ffd61c98c129d6b476362ca4e7 100644
--- a/lib/security.c
+++ b/lib/security.c
@@ -147,7 +147,7 @@ static int ftp_send_command(struct connectdata *conn, const char *message, ...)
 }
 
 /* Read |len| from the socket |fd| and store it in |to|. Return a CURLcode
-   saying whether an error occured or CURLE_OK if |len| was read. */
+   saying whether an error occurred or CURLE_OK if |len| was read. */
 static CURLcode
 socket_read(curl_socket_t fd, void *to, size_t len)
 {
@@ -173,7 +173,7 @@ socket_read(curl_socket_t fd, void *to, size_t len)
 
 
 /* Write |len| bytes from the buffer |to| to the socket |fd|. Return a
-   CURLcode saying whether an error occured or CURLE_OK if |len| was
+   CURLcode saying whether an error occurred or CURLE_OK if |len| was
    written. */
 static CURLcode
 socket_write(struct connectdata *conn, curl_socket_t fd, const void *to,
diff --git a/lib/sendf.c b/lib/sendf.c
index 06b289cbc2fdd063e9ccbffc2deda1bad8bff0a5..3edac5a9023b34fda89fe833c10ae9b4b1d1b20a 100644
--- a/lib/sendf.c
+++ b/lib/sendf.c
@@ -621,7 +621,7 @@ static int showit(struct SessionHandle *data, curl_infotype type,
       size_t i;
       for(i = 0; i < size-4; i++) {
         if(memcmp(&buf[i], "\x0d\x0a\x0d\x0a", 4) == 0) {
-          /* convert everthing through this CRLFCRLF but no further */
+          /* convert everything through this CRLFCRLF but no further */
           conv_size = i + 4;
           break;
         }
diff --git a/lib/smtp.c b/lib/smtp.c
index e14c25f50fdd1b336fb0608d28d0dbae5f95339e..5790fe7441da6988d75691766100a12869e92491 100644
--- a/lib/smtp.c
+++ b/lib/smtp.c
@@ -1108,7 +1108,7 @@ static CURLcode smtp_connect(struct connectdata *conn,
   if(CURLE_OK != result)
     return result;
 
-  /* We always support persistant connections on smtp */
+  /* We always support persistent connections on smtp */
   conn->bits.close = FALSE;
 
   pp->response_time = RESP_TIMEOUT; /* set default response time-out */
diff --git a/lib/socks.c b/lib/socks.c
index 419d1d796ce3e8541efdc866f6b90328afc6c32c..08e4f66f6a2f738edfcbd15f907e38f64179c2e3 100644
--- a/lib/socks.c
+++ b/lib/socks.c
@@ -422,7 +422,7 @@ CURLcode Curl_SOCKS5(const char *proxy_name,
   }
 
   if(result & CURL_CSELECT_ERR) {
-    failf(conn->data, "SOCKS5: error occured during connection");
+    failf(conn->data, "SOCKS5: error occurred during connection");
     return CURLE_COULDNT_CONNECT;
   }
 
@@ -461,7 +461,7 @@ CURLcode Curl_SOCKS5(const char *proxy_name,
   }
 
   if(result & CURL_CSELECT_ERR) {
-    failf(conn->data, "SOCKS5 read error occured");
+    failf(conn->data, "SOCKS5 read error occurred");
     return CURLE_RECV_ERROR;
   }
 
diff --git a/lib/speedcheck.c b/lib/speedcheck.c
index 38bad5a57904633d15a561de6e89074303ee2af3..a43acb3f0ac407e048898a9183411ed9c4aa9c72 100644
--- a/lib/speedcheck.c
+++ b/lib/speedcheck.c
@@ -53,7 +53,7 @@ CURLcode Curl_speedcheck(struct SessionHandle *data,
       /* we have been this slow for long enough, now die */
       failf(data,
             "Operation too slow. "
-            "Less than %ld bytes/sec transfered the last %ld seconds",
+            "Less than %ld bytes/sec transferred the last %ld seconds",
             data->set.low_speed_limit,
             data->set.low_speed_time);
       return CURLE_OPERATION_TIMEDOUT;
diff --git a/lib/ssluse.c b/lib/ssluse.c
index 9d55eb0c36f1be60182d47911e0c2a28d72be80a..1b53f2589af300fbc75ead5bbca857a098963d4b 100644
--- a/lib/ssluse.c
+++ b/lib/ssluse.c
@@ -1200,7 +1200,7 @@ static CURLcode verifyhost(struct connectdata *conn,
     res = CURLE_PEER_FAILED_VERIFICATION;
   }
   else {
-    /* we have to look to the last occurence of a commonName in the
+    /* we have to look to the last occurrence of a commonName in the
        distinguished one to get the most significant one. */
     int j,i=-1 ;
 
@@ -2587,7 +2587,7 @@ static ssize_t ossl_send(struct connectdata *conn,
     case SSL_ERROR_WANT_READ:
     case SSL_ERROR_WANT_WRITE:
       /* The operation did not complete; the same TLS/SSL I/O function
-         should be called again later. This is basicly an EWOULDBLOCK
+         should be called again later. This is basically an EWOULDBLOCK
          equivalent. */
       *curlcode = CURLE_AGAIN;
       return -1;
@@ -2658,7 +2658,7 @@ static ssize_t ossl_recv(struct connectdata *conn, /* connection data */
 size_t Curl_ossl_version(char *buffer, size_t size)
 {
 #ifdef YASSL_VERSION
-  /* yassl provides an OpenSSL API compatiblity layer so it looks identical
+  /* yassl provides an OpenSSL API compatibility layer so it looks identical
      to OpenSSL in all other aspects */
   return snprintf(buffer, size, "yassl/%s", YASSL_VERSION);
 #else /* YASSL_VERSION */
diff --git a/lib/telnet.c b/lib/telnet.c
index 1a76b8b889be1f677efda9ff8fcded443defee94..53f33e9a2bbcd2b7b5a759e484815c9caf49dbe4 100644
--- a/lib/telnet.c
+++ b/lib/telnet.c
@@ -1093,7 +1093,7 @@ CURLcode telrcv(struct connectdata *conn,
           {
             /*
              * This is an error.  We only expect to get "IAC IAC" or "IAC SE".
-             * Several things may have happend.  An IAC was not doubled, the
+             * Several things may have happened.  An IAC was not doubled, the
              * IAC SE was left off, or another option got inserted into the
              * suboption are all possibilities.  If we assume that the IAC was
              * not doubled, and really the IAC SE was left off, we could get
diff --git a/lib/tftp.c b/lib/tftp.c
index ff59acadde43d83cffddf17f44732fcc5f7c0a11..a280330f9c8dd8df2ee2be1e22d78d2e90e069dd 100644
--- a/lib/tftp.c
+++ b/lib/tftp.c
@@ -1276,7 +1276,7 @@ static CURLcode tftp_easy_statemach(struct connectdata *conn)
     else {
 
       if(rc==0) {
-        /* A timeout occured, but our timeout is variable, so maybe
+        /* A timeout occurred, but our timeout is variable, so maybe
            just continue? */
         long rtms = state->retry_time * 1000;
         if (Curl_tvdiff(k->now, transaction_start) > rtms) {
diff --git a/lib/transfer.c b/lib/transfer.c
index 740245e4b9337d47cc2757f54c67d1c9b585d280..6a93bf059775a7b5a458ae956431ce84ace3c0ae 100644
--- a/lib/transfer.c
+++ b/lib/transfer.c
@@ -233,7 +233,7 @@ CURLcode Curl_fillreadbuffer(struct connectdata *conn, int bytes, int *nreadp)
 #endif /* CURL_DOES_CONVERSIONS */
 
     if((nread - hexlen) == 0)
-      /* mark this as done once this chunk is transfered */
+      /* mark this as done once this chunk is transferred */
       data->req.upload_done = TRUE;
 
     nread+=(int)strlen(endofline_native); /* for the added end of line */
@@ -2098,7 +2098,7 @@ CURLcode Curl_retry_request(struct connectdata *conn,
                                 to retry. Marking it this way should
                                 prevent i.e HTTP transfers to return
                                 error just because nothing has been
-                                transfered! */
+                                transferred! */
 
     if(data->state.proto.http->writebytecount)
       Curl_readrewind(conn);
diff --git a/lib/urldata.h b/lib/urldata.h
index 96814cfb5a6d78a29c009da568fdf07e874dd4f6..c77cc34da52d52bc6dfaa45dd244e0f6e465fe85 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -551,7 +551,7 @@ struct SingleRequest {
 
   long headerbytecount;         /* only count received headers */
   long deductheadercount; /* this amount of bytes doesn't count when we check
-                             if anything has been transfered at the end of a
+                             if anything has been transferred at the end of a
                              connection. We use this counter to make only a
                              100 reply (without a following second response
                              code) result in a CURLE_GOT_NOTHING error code */
@@ -778,9 +778,9 @@ struct connectdata {
 
   /* 'primary_ip' and 'primary_port' get filled with peer's numerical
      ip address and port number whenever an outgoing connection is
-     *attemted* from the primary socket to a remote address. When more
+     *attempted* from the primary socket to a remote address. When more
      than one address is tried for a connection these will hold data
-     for the last attempt. When the connection is actualy established
+     for the last attempt. When the connection is actually established
      these are updated with data which comes directly from the socket. */
 
   char primary_ip[MAX_IPADR_LEN];
@@ -997,8 +997,8 @@ struct Progress {
                     force redraw at next call */
   curl_off_t size_dl; /* total expected size */
   curl_off_t size_ul; /* total expected size */
-  curl_off_t downloaded; /* transfered so far */
-  curl_off_t uploaded; /* transfered so far */
+  curl_off_t downloaded; /* transferred so far */
+  curl_off_t uploaded; /* transferred so far */
 
   curl_off_t current_speed; /* uses the currently fastest transfer */