diff --git a/plugins/word-completion/engine.vala b/plugins/word-completion/engine.vala
index eff236042..30f5ed5f8 100644
--- a/plugins/word-completion/engine.vala
+++ b/plugins/word-completion/engine.vala
@@ -48,6 +48,7 @@ public class Euclide.Completion.Parser : GLib.Object {
 
     public bool get_for_word (string to_find, out List<string> list) {
         list = prefix_tree.get_all_matches (to_find);
+        list.remove_link (list.find_custom (to_find, strcmp));
         return list.first () != null;
     }
 
@@ -86,7 +87,7 @@ public class Euclide.Completion.Parser : GLib.Object {
         parsing_cancelled = true;
     }
 
-    private bool parse_string (string text) {
+    public bool parse_string (string text) {
         parsing_cancelled = false;
         string [] word_array = text.split_set (DELIMITERS, MAX_TOKENS);
         foreach (var current_word in word_array ) {
@@ -98,4 +99,43 @@ public class Euclide.Completion.Parser : GLib.Object {
         }
         return true;
     }
+
+    public void delete_word (string word, string text) requires (word.length > 0) {
+        bool match_found = false;
+        uint word_end_index = word.length - 1;
+
+        // Figure out if another instance of a word in another position before trying to delete it
+        // from the prefix tree
+        while (word_end_index > -1 && !match_found) {
+            match_found = prefix_in_text (word[0:word_end_index], text);
+            word_end_index--;
+        }
+
+        // All possible prefixes of the word exist in the source view
+        if (match_found && word_end_index == word.length - 1) {
+            return;
+        }
+
+        uint min_deletion_index = word_end_index + 1;
+
+        lock (prefix_tree) {
+            prefix_tree.remove (word, (int) min_deletion_index);
+        }
+    }
+
+    private bool prefix_in_text (string word, string text) {
+        // If there are at least two matches then the prefix
+        // still exists after the modifications made to the source view
+
+        try {
+            var search_regex = new Regex ("\\b$word\\b");
+            GLib.MatchInfo match_info;
+            search_regex.match_all (text, 0, out match_info);
+            return match_info.get_match_count () > 1;
+        } catch (GLib.Error err) {
+            critical ("Error while attempting regex search of prefix in document text: %s", err.message);
+        }
+
+        return false;
+    }
 }
diff --git a/plugins/word-completion/plugin.vala b/plugins/word-completion/plugin.vala
index d227d12a6..b6c018b53 100644
--- a/plugins/word-completion/plugin.vala
+++ b/plugins/word-completion/plugin.vala
@@ -76,7 +76,8 @@ public class Scratch.Plugins.Completion : Peas.ExtensionBase, Peas.Activatable {
 
         current_document = doc;
         current_view = doc.source_view;
-        current_view.key_press_event.connect (on_key_press);
+        current_view.buffer.insert_text.connect (on_insert_text);
+
         current_view.completion.show.connect (() => {
             completion_in_progress = true;
         });
@@ -120,53 +121,86 @@ public class Scratch.Plugins.Completion : Peas.ExtensionBase, Peas.Activatable {
         return false;
     }
 
-    private bool on_key_press (Gtk.Widget view, Gdk.EventKey event) {
-        var kv = event.keyval;
-        /* Pass through any modified keypress except Shift or Capslock */
-        Gdk.ModifierType mods = event.state & Gdk.ModifierType.MODIFIER_MASK
-                                            & ~Gdk.ModifierType.SHIFT_MASK
-                                            & ~Gdk.ModifierType.LOCK_MASK;
-        if (mods > 0 ) {
-            /* Default key for USER_REQUESTED completion is ControlSpace
-             * but this is trapped elsewhere. Control + USER_REQUESTED_KEY acts as an
-             * alternative and also purges spelling mistakes and unused words from the list.
-             * If used when a word or part of a word is selected, the selection will be
-             * used as the word to find. */
-
-            if ((mods & Gdk.ModifierType.CONTROL_MASK) > 0 &&
-                (kv == REFRESH_SHORTCUT)) {
-
-                parser.rebuild_word_list (current_view);
-                current_view.show_completion ();
-                return true;
-            }
+    private void on_insert_text (Gtk.TextIter pos, string new_text, int new_text_length) {
+
+        if (new_text.strip () == "") {
+            return;
         }
 
-        var uc = (unichar)(Gdk.keyval_to_unicode (kv));
-        if (!completion_in_progress && Euclide.Completion.Parser.is_delimiter (uc) &&
-            (uc.isprint () || uc.isspace ())) {
+        bool starts_word = pos.starts_word ();
+        bool ends_word = pos.ends_word ();
+        bool between_word = pos.inside_word () && !starts_word && !ends_word;
 
-            var buffer = current_view.buffer;
-            var mark = buffer.get_insert ();
-            Gtk.TextIter cursor_iter;
-            buffer.get_iter_at_mark (out cursor_iter, mark);
+        if (ends_word) {
+            this.handle_insert_at_phrase_end (pos, new_text, new_text_length);
+        } else if (between_word) {
+            this.handle_insert_between_phrase (pos, new_text, new_text_length);
+        } else {
+            this.handle_insert_not_at_word_boundary (pos, new_text, new_text_length);
+        }
+    }
 
-            var word_start = cursor_iter;
-            Euclide.Completion.Parser.back_to_word_start (ref word_start);
+    private void handle_insert_between_phrase (Gtk.TextIter pos, string new_text, int new_text_length) {
+        debug ("word-completion: Text inserted between word.\n");
+        var word_start_iter = pos;
+        word_start_iter.backward_word_start ();
+
+        var word_end_iter = pos;
+        word_end_iter.forward_word_end ();
+
+        var old_word_to_delete = word_start_iter.get_text (word_end_iter);
+        parser.delete_word (old_word_to_delete, current_view.buffer.text);
+        
+        // Check if new text ends with whitespace
+        if (ends_with_whitespace (new_text)) {
+            // The text from the insert postiion to the end of the word needs to be added as its own word
+            var final_word_end_iter = pos;
+            final_word_end_iter.forward_word_end ();
+            
+            var extra_word_to_add = pos.get_text (final_word_end_iter);
+            parser.parse_string (extra_word_to_add);
+        }
 
-            string word = buffer.get_text (word_start, cursor_iter, false);
-            parser.add_word (word);
+        var full_phrases = word_start_iter.get_text (pos) + new_text;
+        parser.parse_string (full_phrases);
+    }
+    
+    private bool ends_with_whitespace (string str) {
+        if (str.length == 0) {
+            return false;
+        }
+        
+
+        if (str.get_char (str.length - 1).isspace ()) {
+            return true;
         }
 
         return false;
     }
 
+    private void handle_insert_at_phrase_end (Gtk.TextIter pos, string new_text, int new_text_length) {
+        var text_start_iter = Gtk.TextIter ();
+        text_start_iter = pos;
+        text_start_iter.backward_word_start ();
+
+        var text_end_iter = Gtk.TextIter ();
+        text_end_iter.assign (pos);
+        text_end_iter.forward_chars (new_text_length - 1);
+
+        var full_phrases = text_start_iter.get_text (text_end_iter) + new_text;
+        parser.parse_string (full_phrases);
+    }
+
+    private void handle_insert_not_at_word_boundary (Gtk.TextIter pos, string new_text, int new_text_length) {
+        parser.parse_string (new_text);
+    }
+
     private string provider_name_from_document (Scratch.Services.Document doc) {
         return _("%s - Word Completion").printf (doc.get_basename ());
     }
 
     private void cleanup (Gtk.SourceView view) {
-        current_view.key_press_event.disconnect (on_key_press);
+        current_view.buffer.insert_text.disconnect (on_insert_text);
 
         current_view.completion.get_providers ().foreach ((p) => {
             try {
diff --git a/plugins/word-completion/prefix-tree.vala b/plugins/word-completion/prefix-tree.vala
index ea5ca2d41..14e5fc787 100644
--- a/plugins/word-completion/prefix-tree.vala
+++ b/plugins/word-completion/prefix-tree.vala
@@ -2,7 +2,13 @@
 namespace Scratch.Plugins {
     private class PrefixNode : Object {
         public GLib.List<PrefixNode> children;
-        public unichar value { get; set; }
+        public unichar value { get; construct; }
+
+        public PrefixNode (unichar c = '\0') {
+            Object (
+                value: c
+            );
+        }
 
         construct {
             children = new List<PrefixNode> ();
@@ -17,9 +23,7 @@ namespace Scratch.Plugins {
         }
 
         public void clear () {
-            root = new PrefixNode () {
-                value = '\0'
-            };
+            root = new PrefixNode ();
         }
 
         public void insert (string word) {
@@ -47,9 +51,7 @@ namespace Scratch.Plugins {
                 }
             }
 
-            var new_child = new PrefixNode () {
-                value = curr
-            };
+            var new_child = new PrefixNode (curr);
             node.children.insert_sorted (new_child, (c1, c2) => {
                 if (c1.value > c2.value) {
                     return 1;
@@ -63,8 +65,40 @@ namespace Scratch.Plugins {
             }
         }
 
+        public void remove (string word, int min_deletion_index) {
+            if (word.length == 0) {
+                return;
+            }
+
+            remove_at (word, root, min_deletion_index);
+        }
+
+        private bool remove_at (string word, PrefixNode node, int min_deletion_index, int char_index = 0) {
+            unichar curr;
+
+            word.get_next_char (ref char_index, out curr);
+            if (curr == '\0') {
+                return true;
+            }
+
+            foreach (var child in node.children) {
+                if (child.value == curr) {
+                    bool should_continue = this.remove_at (word, node, min_deletion_index, char_index + 1);
+
+                    if (should_continue && child.children.length () == 0) {
+                        node.children.remove (child);
+                        return char_index < min_deletion_index;
+                    }
+
+                    break;
+                }
+            }
+
+            return false;
+        }
+
         public bool find_prefix (string prefix) {
-            return find_prefix_at (prefix, root) != null? true : false;
+            return find_prefix_at (prefix, root) != null ? true : false;
         }
 
         private PrefixNode? find_prefix_at (string prefix, PrefixNode node, int i = 0) {