diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index 11348b2..f022a4e 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -274,7 +274,7 @@
     Even though IOBase does not declare read, readinto, or write because
     their signatures will vary, implementations and clients should
     consider those methods part of the interface. Also, implementations
-    may raise a IOError when operations they do not support are called.
+    may raise an IOError when operations they do not support are called.
 
     The basic type used for binary data read from or written to a file is
     the bytes type. Method arguments may also be bytearray or memoryview of
diff --git a/Lib/chunk.py b/Lib/chunk.py
index 3e3b5a4..2d15abe 100644
--- a/Lib/chunk.py
+++ b/Lib/chunk.py
@@ -21,7 +21,7 @@
 usage of the Chunk class defined here is to instantiate an instance at
 the start of each chunk and read from the instance until it reaches
 the end, after which a new instance can be instantiated.  At the end
-of the file, creating a new instance will fail with a EOFError
+of the file, creating a new instance will fail with an EOFError
 exception.
 
 Usage:
diff --git a/Lib/codecs.py b/Lib/codecs.py
index 3d9be35..590238e 100644
--- a/Lib/codecs.py
+++ b/Lib/codecs.py
@@ -252,7 +252,7 @@
     """
     def __init__(self, errors='strict'):
         """
-        Creates a IncrementalDecoder instance.
+        Creates an IncrementalDecoder instance.
 
         The IncrementalDecoder may use different error handling schemes by
         providing the errors keyword argument. See the module docstring
@@ -1012,7 +1012,7 @@
     """
     Encoding iterator.
 
-    Encodes the input strings from the iterator using a IncrementalEncoder.
+    Encodes the input strings from the iterator using an IncrementalEncoder.
 
     errors and kwargs are passed through to the IncrementalEncoder
     constructor.
@@ -1030,7 +1030,7 @@
     """
     Decoding iterator.
 
-    Decodes the input strings from the iterator using a IncrementalDecoder.
+    Decodes the input strings from the iterator using an IncrementalDecoder.
 
     errors and kwargs are passed through to the IncrementalDecoder
     constructor.
diff --git a/Lib/distutils/cygwinccompiler.py b/Lib/distutils/cygwinccompiler.py
index c72a249..258e138 100644
--- a/Lib/distutils/cygwinccompiler.py
+++ b/Lib/distutils/cygwinccompiler.py
@@ -347,7 +347,7 @@
 # class Mingw32CCompiler
 
 # Because these compilers aren't configured in Python's pyconfig.h file by
-# default, we should at least warn the user if he is using a unmodified
+# default, we should at least warn the user if he is using an unmodified
 # version.
 
 CONFIG_H_OK = "ok"
diff --git a/Lib/ftplib.py b/Lib/ftplib.py
index 449ce71..3739741 100644
--- a/Lib/ftplib.py
+++ b/Lib/ftplib.py
@@ -264,7 +264,7 @@
         return self.voidcmd(cmd)
 
     def sendeprt(self, host, port):
-        '''Send a EPRT command with the current host and the given port number.'''
+        '''Send an EPRT command with the current host and the given port number.'''
         af = 0
         if self.af == socket.AF_INET:
             af = 1
@@ -842,7 +842,7 @@
 
 
 def parse229(resp, peer):
-    '''Parse the '229' response for a EPSV request.
+    '''Parse the '229' response for an EPSV request.
     Raises error_proto if it does not contain '(|||port|)'
     Return ('host.addr.as.numbers', port#) tuple.'''
 
diff --git a/Lib/idlelib/EditorWindow.py b/Lib/idlelib/EditorWindow.py
index 0c5b713..8a33719 100644
--- a/Lib/idlelib/EditorWindow.py
+++ b/Lib/idlelib/EditorWindow.py
@@ -1384,7 +1384,7 @@
             text.see("insert")
             text.undo_block_stop()
 
-    # Our editwin provides a is_char_in_string function that works
+    # Our editwin provides an is_char_in_string function that works
     # with a Tk text index, but PyParse only knows about offsets into
     # a string. This builds a function for PyParse that accepts an
     # offset.
diff --git a/Lib/idlelib/ReplaceDialog.py b/Lib/idlelib/ReplaceDialog.py
index 9a9f74c..66a871a 100644
--- a/Lib/idlelib/ReplaceDialog.py
+++ b/Lib/idlelib/ReplaceDialog.py
@@ -59,7 +59,7 @@
     def default_command(self, event=None):
         if self.do_find(self.ok):
             if self.do_replace():   # Only find next match if replace succeeded.
-                                    # A bad re can cause a it to fail.
+                                    # A bad re can cause it to fail.
                 self.do_find(0)
 
     def _replace_expand(self, m, repl):
diff --git a/Lib/io.py b/Lib/io.py
index 1438493..53ee102 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -19,7 +19,7 @@
 Another IOBase subclass, TextIOBase, deals with the encoding and decoding
 of streams into text. TextIOWrapper, which extends it, is a buffered text
 interface to a buffered raw stream (`BufferedIOBase`). Finally, StringIO
-is a in-memory stream for text.
+is an in-memory stream for text.
 
 Argument names are not part of the specification, and only the arguments
 of open() are intended to be used as keyword arguments.
diff --git a/Lib/lib2to3/fixes/fix_input.py b/Lib/lib2to3/fixes/fix_input.py
index fbf4c72..728636b 100644
--- a/Lib/lib2to3/fixes/fix_input.py
+++ b/Lib/lib2to3/fixes/fix_input.py
@@ -17,7 +17,7 @@
               """
 
     def transform(self, node, results):
-        # If we're already wrapped in a eval() call, we're done.
+        # If we're already wrapped in an eval() call, we're done.
         if context.match(node.parent.parent):
             return
 
diff --git a/Lib/msilib/schema.py b/Lib/msilib/schema.py
index b84eb22..e132194 100644
--- a/Lib/msilib/schema.py
+++ b/Lib/msilib/schema.py
@@ -733,7 +733,7 @@
 (u'CustomAction',u'Source',u'Y',None, None, None, None, u'CustomSource',None, u'The table reference of the source of the code.',),
 (u'CustomAction',u'Target',u'Y',None, None, None, None, u'Formatted',None, u'Execution parameter, depends on the type of custom action',),
 (u'DrLocator',u'Signature_',u'N',None, None, None, None, u'Identifier',None, u'The Signature_ represents a unique file signature and is also the foreign key in the Signature table.',),
-(u'DrLocator',u'Path',u'Y',None, None, None, None, u'AnyPath',None, u'The path on the user system. This is a either a subpath below the value of the Parent or a full path. The path may contain properties enclosed within [ ] that will be expanded.',),
+(u'DrLocator',u'Path',u'Y',None, None, None, None, u'AnyPath',None, u'The path on the user system. This is either a subpath below the value of the Parent or a full path. The path may contain properties enclosed within [ ] that will be expanded.',),
 (u'DrLocator',u'Depth',u'Y',0,32767,None, None, None, None, u'The depth below the path to which the Signature_ is recursively searched. If absent, the depth is assumed to be 0.',),
 (u'DrLocator',u'Parent',u'Y',None, None, None, None, u'Identifier',None, u'The parent file signature. It is also a foreign key in the Signature table. If null and the Path column does not expand to a full path, then all the fixed drives of the user system are searched using the Path.',),
 (u'DuplicateFile',u'File_',u'N',None, None, u'File',1,u'Identifier',None, u'Foreign key referencing the source file to be duplicated.',),
diff --git a/Lib/test/decimaltestdata/fma.decTest b/Lib/test/decimaltestdata/fma.decTest
index a8197ef..ee2a8d4 100644
--- a/Lib/test/decimaltestdata/fma.decTest
+++ b/Lib/test/decimaltestdata/fma.decTest
@@ -148,7 +148,7 @@
 fmax2019 fma -9.999999  9.999999  0E+999999  -> -100.000 Inexact Rounded
 fmax2020 fma -9.999999 -9.999999  0E+999999  ->  100.000 Inexact Rounded
 
--- 1999.12.21: next one is a edge case if intermediate longs are used
+-- 1999.12.21: next one is an edge case if intermediate longs are used
 precision: 15
 fmax2059 fma 999999999999 9765625  0E+999999  -> 9.76562499999023E+18 Inexact Rounded
 precision: 30
diff --git a/Lib/test/decimaltestdata/multiply.decTest b/Lib/test/decimaltestdata/multiply.decTest
index 6a23d5a..e8bd77a 100644
--- a/Lib/test/decimaltestdata/multiply.decTest
+++ b/Lib/test/decimaltestdata/multiply.decTest
@@ -49,7 +49,7 @@
 mulx019 multiply -9.999999999  9.999999999 -> -100.000 Inexact Rounded
 mulx020 multiply -9.999999999 -9.999999999 ->  100.000 Inexact Rounded
 
--- 1999.12.21: next one is a edge case if intermediate longs are used
+-- 1999.12.21: next one is an edge case if intermediate longs are used
 precision: 15
 mulx059 multiply 999999999999 9765625 -> 9.76562499999023E+18 Inexact Rounded
 precision: 30
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index 57c7c88..fb34893 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -649,7 +649,7 @@
         except OSError as e:
             self.assertEqual(e.errno, errno.EBADF)
         else:
-            self.fail("%r didn't raise a OSError with a bad file descriptor"
+            self.fail("%r didn't raise an OSError with a bad file descriptor"
                       % f)
 
     @unittest.skipUnless(hasattr(os, 'isatty'), 'test needs os.isatty()')
diff --git a/Lib/test/test_support.py b/Lib/test/test_support.py
index 85f9965..89c5719 100644
--- a/Lib/test/test_support.py
+++ b/Lib/test/test_support.py
@@ -196,7 +196,7 @@
         # The exponential backoff of the timeout amounts to a total
         # of ~1 second after which the deletion is probably an error
         # anyway.
-        # Testing on a i7@4.3GHz shows that usually only 1 iteration is
+        # Testing on an i7@4.3GHz shows that usually only 1 iteration is
         # required when contention occurs.
         timeout = 0.001
         while timeout < 1.0:
diff --git a/Lib/xmlrpclib.py b/Lib/xmlrpclib.py
index e072f71..b0e7485 100644
--- a/Lib/xmlrpclib.py
+++ b/Lib/xmlrpclib.py
@@ -970,7 +970,7 @@
                   "unexpected type in multicall result"
 
 class MultiCall:
-    """server -> a object used to boxcar method calls
+    """server -> an object used to boxcar method calls
 
     server should be a ServerProxy object.
 
@@ -1334,7 +1334,7 @@
     ##
     # Create parser.
     #
-    # @return A 2-tuple containing a parser and a unmarshaller.
+    # @return A 2-tuple containing a parser and an unmarshaller.
 
     def getparser(self):
         # get parser and unmarshaller