diff --git a/lisp/language/thai-word.el b/lisp/language/thai-word.el
index 5584461bf4f..ee8db1f2708 100644
--- a/lisp/language/thai-word.el
+++ b/lisp/language/thai-word.el
@@ -10805,7 +10805,7 @@ the current word list."
 
 
 ;; Move point forward to the end of Thai word which follows point and
-;; update VEC.	VEC is a vector of three elements used to cache word
+;; update VEC.  VEC is a vector of three elements used to cache word
 ;; end positions.  The Nth element, if non-nil, is a list of end
 ;; points of the Nth word, or t indicating that there is no Thai
 ;; character.  LIMIT limits the point movement.
@@ -10886,7 +10886,7 @@ the current word list."
 	  nil)
 	(progn
 	  ;; We found four succeeding Thai words (or LIMIT has been
-	  ;; reached).	Move to the end of the first word.
+	  ;; reached).  Move to the end of the first word.
 	  (goto-char (car v0))
 	  ;; Update VEC for the next function call.  If no larger word
 	  ;; positions have been found, set the corresponding vector
@@ -10899,7 +10899,7 @@ the current word list."
 	      (aset vec 1 v2)
 	      (aset vec 2 v3)))) ; exit function successfully
 
-      ;; We didn't find four consecutive words.	 If we have found a
+      ;; We didn't find four consecutive words.  If we have found a
       ;; `second best' solution and the length of those two words is
       ;; longer than the longest word we can see at the current point,
       ;; adopt the second best solution.  This decision is based on
diff --git a/lisp/play/landmark.el b/lisp/play/landmark.el
index 1bd1c7ec48a..f947a8caeaa 100644
--- a/lisp/play/landmark.el
+++ b/lisp/play/landmark.el
@@ -75,7 +75,7 @@
 ;; The board is a rectangular grid. We code empty squares with 0, X's with 1
 ;; and O's with 6. The rectangle is recorded in a one dimensional vector
 ;; containing padding squares (coded with -1). These squares allow us to
-;; detect when we are trying to move out of the board.	We denote a square by
+;; detect when we are trying to move out of the board.  We denote a square by
 ;; its (X,Y) coords, or by the INDEX corresponding to them in the vector.  The
 ;; leftmost topmost square has coords (1,1) and index lm-board-width + 2.
 ;; Similarly, vectors between squares may be given by two DX, DY coords or by
diff --git a/lisp/progmodes/compile.el b/lisp/progmodes/compile.el
index cc1fe1ef827..04a5cf9cad7 100644
--- a/lisp/progmodes/compile.el
+++ b/lisp/progmodes/compile.el
@@ -61,7 +61,7 @@
 
 ;; TYPE is 0 for info or 1 for warning if the message matcher identified it as
 ;; such, 2 otherwise (for a real error).  END-LOC is a LOC pointing to the
-;; other end, if the parsed message contained a range.	If the end of the
+;; other end, if the parsed message contained a range.  If the end of the
 ;; range didn't specify a COLUMN, it defaults to -1, meaning end of line.
 ;; These are the value of the `message' text-properties in the compilation
 ;; buffer.
@@ -499,7 +499,7 @@ This only affects platforms that support asynchronous processes (see
 
 ;; A weak per-compilation-buffer hash indexed by (FILENAME . DIRECTORY).  Each
 ;; value is a FILE-STRUCTURE as described above, with the car eq to the hash
-;; key.	 This holds the tree seen from root, for storing new nodes.
+;; key.  This holds the tree seen from root, for storing new nodes.
 (defvar compilation-locs ())
 
 (defvar compilation-debug nil
@@ -627,12 +627,12 @@ Faces `compilation-error-face', `compilation-warning-face',
       keymap compilation-button-map
       help-echo "mouse-2: visit this directory")))
 
-;; Data type `reverse-ordered-alist' retriever.	 This function retrieves the
+;; Data type `reverse-ordered-alist' retriever.  This function retrieves the
 ;; KEY element from the ALIST, creating it in the right position if not already
 ;; present. ALIST structure is
 ;; '(ANCHOR (KEY1 ...) (KEY2 ...)... (KEYn ALIST ...))
 ;; ANCHOR is ignored, but necessary so that elements can be inserted.  KEY1
-;; may be nil.	The other KEYs are ordered backwards so that growing line
+;; may be nil.  The other KEYs are ordered backwards so that growing line
 ;; numbers can be inserted in front and searching can abort after half the
 ;; list on average.
 (eval-when-compile		    ;Don't keep it at runtime if not needed.
diff --git a/lisp/scroll-all.el b/lisp/scroll-all.el
index 9e816480f38..c659768bc52 100644
--- a/lisp/scroll-all.el
+++ b/lisp/scroll-all.el
@@ -28,7 +28,7 @@
 ;;    up or down lines in any buffer causes all the buffers to mirror
 ;;    the scrolling.  It hooks into the post-command-hook to check for
 ;;    potential scrolling commands and if we're locked, mirrors them in all
-;;    windows.	This allows us to grab line-at-a-time scrolling as well as
+;;    windows.  This allows us to grab line-at-a-time scrolling as well as
 ;;    screen-at-a-time scrolling, and doesn't remap any of the keyboard
 ;;    commands to do it.