diff --git a/contrib/header-tools/README b/contrib/header-tools/README
index f4eee329b333768c12dac896ed38041539eeff0d..fee7b7cf3fb4d0453bbc880a0a6b422b12b59fe2 100644
--- a/contrib/header-tools/README
+++ b/contrib/header-tools/README
@@ -37,7 +37,7 @@ gcc-order-headers
   command line.
 
   Any files which are changed are output, and the original is saved with a
-  .bak extention.
+  .bak extension.
 
   ex.:     gcc-order-headers tree-ssa.cc c/c-decl.cc
 
@@ -198,7 +198,7 @@ reduce-headers
 
   A small subset of targets has been determined to provide excellent coverage,
   at least as of Aug 31/15 .  They were found by reducing all the files
-  contained in libbackend.a oer a full set of targets(207).  All conditions
+  contained in libbackend.a over a full set of targets(207).  All conditions
   which disallowed removal of a header file were triggered by one or more of
   these targets.  They are also known to the tool.  When building targets it
   will check those targets before the rest.  
@@ -212,7 +212,7 @@ reduce-headers
   example:
 
   mkdir gcc          // checkout gcc in subdir gcc
-  mdsir build        // boostrap gcc in subdir build
+  mkdir build        // boostrap gcc in subdir build
   mkdir target       // create target directory and run config-list.mk
   cd gcc/gcc