Universally adopt most conventional spelling of acquire.

sys/dev/lmc/if_lmc.c

@@ -58,7 +58,7 @@
  * interface and add an Ethernet-to-HDLC gate array to make a WAN card.
  * David Boggs designed the Ethernet-to-HDLC gate arrays and PC cards.
  * We did this at our company, LAN Media Corporation (LMC).
- * SBE Corp aquired LMC and continues to make the cards.
+ * SBE Corp acquired LMC and continues to make the cards.
  *
  * Since the cards use Tulip Ethernet chips, we started with Matt Thomas'
  * ubiquitous "de" driver.  Michael Graff stripped out the Ethernet stuff

sys/dev/sk/if_sk.c

@@ -58,7 +58,7 @@ __FBSDID("$FreeBSD$");
  *  http://www.freebsd.org/~wpaul/SysKonnect/xmacii_datasheet_rev_c_9-29.pdf
  *	The SysKonnect GEnesis manual, http://www.syskonnect.com
  *
- * Note: XaQti has been aquired by Vitesse, and Vitesse does not have the
+ * Note: XaQti has been acquired by Vitesse, and Vitesse does not have the
  * XMAC II datasheet online. I have put my copy at people.freebsd.org as a
  * convenience to others until Vitesse corrects this problem:
  *

sys/kern/kern_mtxpool.c

@@ -24,7 +24,7 @@
  */
 
 /* Mutex pool routines.  These routines are designed to be used as short
- * term leaf mutexes (e.g. the last mutex you might aquire other then
+ * term leaf mutexes (e.g. the last mutex you might acquire other then
  * calling msleep()).  They operate using a shared pool.  A mutex is chosen
  * from the pool based on the supplied pointer (which may or may not be
  * valid).

sys/kern/kern_resource.c

@@ -1157,7 +1157,7 @@ uihold(uip)
  *   that we don't need to free, simply unlock and return.
  * Suboptimal case:
  *   If refcount lowering results in need to free, bump the count
- *   back up, lose the lock and aquire the locks in the proper
+ *   back up, lose the lock and acquire the locks in the proper
  *   order to try again.
  */
 void

sys/kern/vfs_lookup.c

@@ -795,7 +795,7 @@ lookup(struct nameidata *ndp)
 
 /*
  * relookup - lookup a path name component
- *    Used by lookup to re-aquire things.
+ *    Used by lookup to re-acquire things.
  */
 int
 relookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)

sys/kern/vfs_subr.c

@@ -2146,7 +2146,7 @@ vrele(struct vnode *vp)
 /*
  * Release an already locked vnode.  This give the same effects as
  * unlock+vrele(), but takes less time and avoids releasing and
- * re-aquiring the lock (as vrele() aquires the lock internally.)
+ * re-aquiring the lock (as vrele() acquires the lock internally.)
  */
 void
 vput(struct vnode *vp)

sys/netgraph/bluetooth/socket/ng_btsocket_l2cap.c

@@ -1974,7 +1974,7 @@ ng_btsocket_l2cap_attach(struct socket *so, int proto, struct thread *td)
 	 * 2) When we need to accept new incomming connection and call 
 	 *    sonewconn()
 	 *
-	 * In the first case we must aquire ng_btsocket_l2cap_sockets_mtx.
+	 * In the first case we must acquire ng_btsocket_l2cap_sockets_mtx.
 	 * In the second case we hold ng_btsocket_l2cap_sockets_mtx already.
 	 * So we now need to distinguish between these cases. From reading
 	 * /sys/kern/uipc_socket.c we can find out that sonewconn() calls

sys/netgraph/ng_base.c

@@ -848,7 +848,8 @@ ng_name_node(node_p node, const char *name)
  *
  * Returns the node if found, else NULL.
  * Eventually should add something faster than a sequential search.
- * Note it aquires a reference on the node so you can be sure it's still there.
+ * Note it acquires a reference on the node so you can be sure it's still
+ * there.
  */
 node_p
 ng_name2noderef(node_p here, const char *name)