diff --git a/array.c b/array.c
index a82ab64dd7..1dd82ad28e 100644
--- a/array.c
+++ b/array.c
@@ -3707,7 +3707,7 @@ ary_append(VALUE x, VALUE y)
 
 /*
  *  call-seq:
- *     ary.concat(other_ary1, other_ary2,...)   -> ary
+ *     ary.concat(other_ary1, other_ary2, ...)   -> ary
  *
  *  Appends the elements of <code>other_ary</code>s to +self+.
  *
@@ -4399,7 +4399,7 @@ rb_ary_or(VALUE ary1, VALUE ary2)
 
 /*
  *  call-seq:
- *     ary.union(other_ary1, other_ary2,...)   -> ary
+ *     ary.union(other_ary1, other_ary2, ...)   -> ary
  *
  *  Set Union --- Returns a new array by joining <code>other_ary</code>s with +self+,
  *  excluding any duplicates and preserving the order from the given arrays.
diff --git a/file.c b/file.c
index bdec438217..66f62024d8 100644
--- a/file.c
+++ b/file.c
@@ -2497,7 +2497,7 @@ chown_internal(const char *path, void *arg)
 
 /*
  *  call-seq:
- *     File.chown(owner_int, group_int, file_name,... )  ->  integer
+ *     File.chown(owner_int, group_int, file_name, ...)  ->  integer
  *
  *  Changes the owner and group of the named file(s) to the given
  *  numeric owner and group id's. Only a process with superuser
@@ -2751,7 +2751,7 @@ utime_internal_i(int argc, VALUE *argv, int follow)
 
 /*
  * call-seq:
- *  File.utime(atime, mtime, file_name,...)   ->  integer
+ *  File.utime(atime, mtime, file_name, ...)   ->  integer
  *
  * Sets the access and modification times of each named file to the
  * first two arguments. If a file is a symlink, this method acts upon
@@ -2770,7 +2770,7 @@ rb_file_s_utime(int argc, VALUE *argv)
 
 /*
  * call-seq:
- *  File.lutime(atime, mtime, file_name,...)   ->  integer
+ *  File.lutime(atime, mtime, file_name, ...)   ->  integer
  *
  * Sets the access and modification times of each named file to the
  * first two arguments. If a file is a symlink, this method acts upon
diff --git a/string.c b/string.c
index 5fb2d2bdb7..f61243d8bb 100644
--- a/string.c
+++ b/string.c
@@ -2975,7 +2975,7 @@ rb_str_concat_literals(size_t num, const VALUE *strary)
 
 /*
  *  call-seq:
- *     str.concat(obj1, obj2,...)          -> str
+ *     str.concat(obj1, obj2, ...)          -> str
  *
  *  Concatenates the given object(s) to <i>str</i>. If an object is an
  *  <code>Integer</code>, it is considered a codepoint and converted
@@ -3095,7 +3095,7 @@ rb_str_concat(VALUE str1, VALUE str2)
 
 /*
  *  call-seq:
- *     str.prepend(other_str1, other_str2,...)  -> str
+ *     str.prepend(other_str1, other_str2, ...)  -> str
  *
  *  Prepend---Prepend the given strings to <i>str</i>.
  *
@@ -6683,7 +6683,7 @@ rb_str_downcase_bang(int argc, VALUE *argv, VALUE str)
  *    This option cannot be combined with any other option.
  *  :turkic ::
  *    Full Unicode case mapping, adapted for Turkic languages
- *    (Turkish, Azerbaijani,...). This means that upper case I is mapped to
+ *    (Turkish, Azerbaijani, ...). This means that upper case I is mapped to
  *    lower case dotless i, and so on.
  *  :lithuanian ::
  *    Currently, just full Unicode case mapping. In the future, full Unicode