I corrected many small grammar errors in the comments: I didn't change the executable code.

build/HELP

@@ -14,14 +14,14 @@ build_main.sh [options] build_xmlstream "file.xhtml"
 build_main.sh [options] process_file "file.xhtml" [processor.xsl]
   Generate output from an xhtml file as if it would be processed during the
   build. Output is written to STDOUT and can be redirected as desired.
-  If a xslt file is not given, it will be choosen automatically.
+  If a xslt file is not given, it will be chosen automatically.
 
 build_main.sh [options] tree_maker [input_dir] "destination_dir"
   Generate a set of make rules to build the website contained in input_dir.
   destination_dir should be the www root of a web server.
   If input_dir is omitted, it will be the source directory determined from
   the build scripts location.
-  Note: if destination_dir is set via previous options, and only one paramter
+  Note: if destination_dir is set via previous options, and only one parameter
   is given, then this parameter will be interpreted as input_dir
 
 build_main.sh [options] wakeup [date]
@@ -42,7 +42,7 @@ OPTIONS
 --source "source_dir"
   Force a specific source directory. If not explicitly given source_dir is
   determined from the build scripts own location. 
-  Pathes given in .sources files are interpreted as relative to source_dir
+  Paths given in .sources files are interpreted as relative to source_dir
   making this option useful when building a webpage outside of the build
   scripts "regular" tree.
 

build/filenames.sh

@@ -6,7 +6,7 @@ inc_filenames=true
 list_langs(){
   # list all languages a file exists in by globbing up
   # the shortname (i.e. file path with file ending omitted)
-  # output is readily formated for inclusion
+  # output is readily formatted for inclusion
   # in xml stream
   shortname="$1"
 

build/translations.sh

@@ -6,7 +6,7 @@ inc_translations=true
 
 get_textsfile(){
   # get the texts file for a given language
-  # fall back to english if necessary
+  # fall back to English if necessary
   lang="$1"
 
   if [ -f "$basedir/tools/texts-${1}.xml" ]; then

build/xslt/fsfe_followupsection.xsl

@@ -7,8 +7,8 @@
       <xsl:attribute name="id">followup</xsl:attribute>
          <!--
          TODO Okay, so the idea here is to be able to display different "followup" boxes. I would suggest doing it like this:
-          - the xml page shold be able to say that it wants to show a
+          - the xml page should be able to say that it wants to show a
-              specific boxe and would contain e.g.
+              specific box and would contain e.g.
               <followup>subscribe-newsletter</followup> so the page would show
               the following box.
           - if the xml page does not contain any <followup> variable, then we should be able to set a default followup box on our own.

build/xslt/fsfe_head.xsl

@@ -163,7 +163,7 @@
     <!-- EXTRACT -->
     <!-- take a first extract which should be sufficient for most pages -->
     <xsl:variable name="extract1">
-      <!-- retreive the first 200 letters of the first p element after h1 -->
+      <!-- retrieve the first 200 letters of the first p element after h1 -->
       <xsl:value-of select="substring(normalize-space(body/h1[1]/following::p[1]),1,200)" />
     </xsl:variable>
     <!-- measure first extract length -->
@@ -180,7 +180,7 @@
         <!-- case: first extract is too short -->
         <xsl:otherwise>
           <xsl:variable name="extract2">
-            <!-- retreive the first 200 letters of the *second* p element after h1 -->
+            <!-- retrieve the first 200 letters of the *second* p element after h1 -->
             <xsl:value-of select="substring(normalize-space(body/h1[1]/following::p[2]),1,200)" />
           </xsl:variable>
           <!-- measure *second* extract length -->

build/xslt/support_js.xsl

@@ -33,7 +33,7 @@
   <xsl:template name="support-form-javascript">
     <script type="text/javascript" src="/scripts/jquery.validate.min.js"></script>
     <!-- 
-        script type="text/javascript" src="/scripts/jquery.validate-lozalization/messages_fi.js"></script 
+        script type="text/javascript" src="/scripts/jquery.validate-localization/messages_fi.js"></script 
         *How to inser lang code in above?*
      -->
     <script type="text/javascript">

events/events.ics.xsl

@@ -89,7 +89,7 @@
   <xsl:template name="ical-escape">
     <xsl:param name="text" />
     
-    <!-- characters to be backslahed: \;, -->
+    <!-- characters to be backslashed: \;, -->
     <xsl:value-of select="str:replace(str:replace(str:replace($text,'\','\\'),',','\,'),';','\;')" />
   </xsl:template>
 

tools/check-translation-status.sh

@@ -41,7 +41,7 @@ if [ "$1" = "" ] || [ -z "$FILE" ]; then
   exit 0
 fi
 
-# -o supresses all other output (-q), and implicates -a
+# -o suppresses all other output (-q), and implicates -a
 if [ ! -z "$ONLY" ]; then
   QUIET="1"
   ALL="1"

tools/update_xmllists.sh

@@ -10,7 +10,7 @@
 #   in phase 2 are built into pages listing all news items and events for a
 #   tag.
 #
-# * tags/.tags.??.xml with a list of the tags useed.
+# * tags/.tags.??.xml with a list of the tags used.
 #
 # * <dir>/.<base>.xmllist for each <dir>/<base>.sources as well as for each
 #   tags/tagged-<tags>.en.xhtml. These files are used in phase 2 to include the

tools/xsltsl/string.xsl

@@ -156,7 +156,7 @@
     </refparameter>
 
     <refreturn>
-      <para>Returns string with first character uppcase and all remaining characters lowercase.</para>
+      <para>Returns string with first character uppercase and all remaining characters lowercase.</para>
     </refreturn>
   </doc:template>
 
@@ -232,7 +232,7 @@
     </refparameter>
 
     <refreturn>
-      <para>Returns string with first character uppcase and all remaining characters lowercase.</para>
+      <para>Returns string with first character uppercase and all remaining characters lowercase.</para>
     </refreturn>
   </doc:template>