diff --git a/fcore/cursor.sml b/fcore/cursor.sml
index 3b13156..09dbf38 100644
--- a/fcore/cursor.sml
+++ b/fcore/cursor.sml
@@ -604,9 +604,11 @@ struct
 
   (* equivalent of vi's 'b' command *)
   val prevWord = ViWordDfa.startOfCurrentWord
+  val prevWordStrict = ViWordDfa.startOfCurrentWordStrict
 
   (* equivalent of vi's 'B' command *)
   val prevWORD = ViWORDDfa.startOfCurrentWORD
+  val prevWORDStrict = ViWORDDfa.startOfCurrentWORDStrict
 
   (* equivalent of vi's 'ge' command *)
   val endOfPrevWord = ViWordDfa.endOfPrevWord
diff --git a/fcore/normal-mode/normal-delete.sml b/fcore/normal-mode/normal-delete.sml
index 2150945..954aa54 100644
--- a/fcore/normal-mode/normal-delete.sml
+++ b/fcore/normal-mode/normal-delete.sml
@@ -380,4 +380,59 @@ struct
       else
         helpDeleteToMatch (app, newCursorIdx, cursorIdx)
     end
+
+  fun deleteInsideWord (app: app_type) =
+    let
+      val {buffer, cursorIdx, searchString, ...} = app
+      val buffer = LineGap.goToIdx (cursorIdx, buffer)
+      val low = Cursor.prevWordStrict (buffer, cursorIdx, 1)
+      val high = Cursor.endOfWordForDelete (buffer, cursorIdx, 1)
+    in
+      if low = high then
+        app
+      else
+        let
+          val length = high - low
+          val buffer = LineGap.delete (low, length, buffer)
+
+          val buffer = LineGap.goToEnd buffer
+          val initialMsg = [SEARCH (buffer, searchString)]
+
+          val buffer = LineGap.goToIdx (low + 777, buffer)
+          val searchList =
+            SearchList.buildRange (buffer, searchString, low - 777)
+
+          val buffer = LineGap.goToIdx (low, buffer)
+        in
+          Finish.buildTextAndClear (app, buffer, low, searchList, initialMsg)
+        end
+    end
+
+  fun deleteInsideWORD (app: app_type) =
+    let
+      val {buffer, cursorIdx, searchString, ...} = app
+      val buffer = LineGap.goToIdx (cursorIdx, buffer)
+      val low = Cursor.prevWORDStrict (buffer, cursorIdx, 1)
+      val high = Cursor.endOfWORDForDelete (buffer, cursorIdx, 1)
+    in
+      if low = high then
+        app
+      else
+        let
+          val length = high - low
+          val buffer = LineGap.delete (low, length, buffer)
+
+          val buffer = LineGap.goToEnd buffer
+          val initialMsg = [SEARCH (buffer, searchString)]
+
+          val buffer = LineGap.goToIdx (low + 777, buffer)
+          val searchList =
+            SearchList.buildRange (buffer, searchString, low - 777)
+
+          val buffer = LineGap.goToIdx (low, buffer)
+        in
+
+          Finish.buildTextAndClear (app, buffer, low, searchList, initialMsg)
+        end
+    end
 end
diff --git a/fcore/normal-mode/normal-mode.sml b/fcore/normal-mode/normal-mode.sml
index 1921474..d9a102a 100644
--- a/fcore/normal-mode/normal-mode.sml
+++ b/fcore/normal-mode/normal-mode.sml
@@ -146,6 +146,7 @@ struct
            | #"f" => appendChr (app, chr, str)
            | #"F" => appendChr (app, chr, str)
            | #"g" => appendChr (app, chr, str)
+           | #"i" => appendChr (app, chr, str)
            (* invalid command: reset mode *)
            | _ => Finish.clearMode app)
       | KEY_ESC => Finish.clearMode app
@@ -209,6 +210,16 @@ struct
                Finish.resizeText (app, width, height)
            | WITH_SEARCH_LIST searchList =>
                Finish.withSearchList (app, searchList))
+      | #"i" =>
+          (case newCmd of
+             CHAR_EVENT #"w" => NormalDelete.deleteInsideWord app
+           | CHAR_EVENT #"W" => NormalDelete.deleteInsideWORD app
+           | CHAR_EVENT _ => Finish.clearMode app
+           | KEY_ESC => Finish.clearMode app
+           | RESIZE_EVENT (width, height) =>
+               Finish.resizeText (app, width, height)
+           | WITH_SEARCH_LIST searchList =>
+               Finish.withSearchList (app, searchList))
       | _ => Finish.clearMode app
 
   (* useful reference as list of non-terminal commands *)