diff --git a/Gemfile b/Gemfile
index bef159b..c58fe8a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -42,6 +42,10 @@ gem 'autoprefixer-rails', '~> 9.6.1'
 
 gem 'bh', '~> 1.3.6'
 
+# Use Diffy for showing translation diffs
+gem 'diffy'
+gem 'diff-lcs'
+
 gem 'will_paginate', '~> 3.1.8'
 gem 'will-paginate-i18n', '~> 0.1.15'
 gem 'will_paginate-bootstrap', '~> 1.0.2'
diff --git a/Gemfile.lock b/Gemfile.lock
index 780d8ea..beaec11 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -86,6 +86,8 @@ GEM
       railties (>= 4.1.0)
       responders
       warden (~> 1.2.3)
+    diff-lcs (1.3)
+    diffy (3.3.0)
     docile (1.3.2)
     erubi (1.8.0)
     execjs (2.7.0)
@@ -252,6 +254,8 @@ DEPENDENCIES
   codacy-coverage
   coffee-rails (~> 5.0.0)
   devise (~> 4.7.1)
+  diff-lcs
+  diffy
   jbuilder (~> 2.9.1)
   jquery-rails (~> 4.3.5)
   mysql2 (~> 0.5.2)
diff --git a/app/assets/javascripts/mathjax-config.js b/app/assets/javascripts/mathjax-config.js
index 9dacc40..45f1478 100644
--- a/app/assets/javascripts/mathjax-config.js
+++ b/app/assets/javascripts/mathjax-config.js
@@ -3,7 +3,8 @@ window.MathJax = {
     tex2jax: {
         inlineMath: [ ["$","$"], ["\\(","\\)"] ],
         displayMath: [ ["$$","$$"], ["\\[","\\]"] ],
-        processEscapes: true
+        processEscapes: true,
+        ignoreClass: "mathjax_ignore|diff"
     },
     "HTML-CSS": { availableFonts: ["TeX"] }
 };
\ No newline at end of file
diff --git a/app/assets/stylesheets/application.css.scss b/app/assets/stylesheets/application.css.scss
index 0ac4783..da8e9b4 100644
--- a/app/assets/stylesheets/application.css.scss
+++ b/app/assets/stylesheets/application.css.scss
@@ -55,6 +55,33 @@ body {
   margin: 20px -30px 0;
 }
 
+/* Style for translation diffs */
+
+.diff {
+  overflow:auto;
+  margin-bottom: 20px;
+  ul{background:#fff;overflow:auto;font-size:13px;list-style:none;margin:0;padding:0;display:table;width:100%;}
+  del, ins{display:block;text-decoration:none;}
+  li {
+    padding:0;
+    display:table-row;
+    margin: 0;
+    height:1em;
+    ins {
+      background:#dfd;
+      color:#080;
+      strong{font-weight:normal;background:#9f9;}
+    }
+    del {
+      background:#fee;
+      color:#b00;
+      strong{font-weight:normal;background:#fcc;}
+    }
+    /* try 'whitespace:pre;' if you don't want lines to wrap */
+    del, ins, span {white-space:pre-wrap;font-family:courier;}
+  }
+}
+
 /* Custom css for fixing styles within problem content */
 
 .problem-content {
diff --git a/app/views/admin/translations/show.html.erb b/app/views/admin/translations/show.html.erb
index efe40c1..7e5bd73 100644
--- a/app/views/admin/translations/show.html.erb
+++ b/app/views/admin/translations/show.html.erb
@@ -7,11 +7,6 @@
   <h1><%= @translation.title %> <small><%= t 'problems.show.problem_subtitle', id: @translation.problem_id %></small></h1>
 </div>
 
-<% if @translation.problem.is_translated? %>
-  <div class="alert alert-warning" role="alert"><%= t('.already_translated') %> <%= link_to t('.visit_current_translation'), @translation.problem, target: '_blank', class: 'alert-link' %></div>
-<% else %>
-  <div class="alert alert-info" role="alert"><%= t('.is_new_translation') %></div>
-<% end %>
 <% if @translation.pending? %>
   <%= link_to admin_translation_decline_path(@translation), method: :post, class: 'btn btn-default btn-sm pull-right' do %>
     <%= icon :remove %> <%= t '.decline_translation' %>
@@ -26,6 +21,21 @@
         <%= sanitize @translation.content, scrubber: TranslationContentScrubber.new %>
     </div>
 <% end %>
+
+<% if @translation.problem.is_translated? %>
+  <% if @translation.title != @translation.problem.title %>
+    <h3><%= t 'activerecord.attributes.translation.title' %></h3>
+    <p><%= t '.changed_title_html', old: @translation.problem.title, new: @translation.title %></p>
+  <% end %>
+  <h3><%= t 'activerecord.attributes.translation.content' %></h3>
+  <%= raw Diffy::Diff.new(@translation.problem.content, @translation.content, allow_empty_diff: false).to_s(:html) %>
+  <div class="alert alert-warning" role="alert"><%= t('.already_translated') %> <%= link_to t('.visit_current_translation'), @translation.problem, target: '_blank', class: 'alert-link' %></div>
+<% else %>
+  <h2><%= t 'activerecord.attributes.translation.content' %></h2>
+  <%= raw Diffy::Diff.new(@translation.content, @translation.content, allow_empty_diff: false).to_s(:html) %>
+  <div class="alert alert-info" role="alert"><%= t('.is_new_translation') %></div>
+<% end %>
+
 <div class="text-center">
   <%= link_to t('problems.show.view_original_problem'), @translation.problem.original_url, target: '_blank' %>
 </div>
diff --git a/app/views/layouts/_header.html.erb b/app/views/layouts/_header.html.erb
index ea1d6e9..4964aa2 100644
--- a/app/views/layouts/_header.html.erb
+++ b/app/views/layouts/_header.html.erb
@@ -15,18 +15,17 @@
         <% end %>
         <%= nav class: 'navbar-right' do %>
             <% if user_signed_in? %>
-              <span class="navbar-text">Eingeloggt als <b>
-                <%= current_user.name %>
+              <span class="navbar-text"><%= t 'application.logged_in_as_html', name: current_user.name %>
                 <% if current_user.admin? %>
-                  <%= icon :star %>
+                  <b><%= icon :star %></b>
                 <% end %>
-              </b></span>
+              </span>
               <%= link_to(t('application.sign_out'), destroy_user_session_path, method: :delete) %>
             <% else %>
               <% if Rails.env.development? %>
-                <%= link_to(t('application.sign_in'), user_developer_omniauth_authorize_path) %>
+                <%= link_to(t('application.sign_in_with_github'), user_developer_omniauth_authorize_path) %>
               <% else %>
-                <%= link_to(t('application.sign_in'), user_github_omniauth_authorize_path) %>
+                <%= link_to(t('application.sign_in_with_github'), user_github_omniauth_authorize_path) %>
               <% end %>
             <% end %>
         <% end %>
diff --git a/app/views/shared/_authors.de.html.erb b/app/views/shared/_authors.de.html.erb
index af50f13..693b573 100644
--- a/app/views/shared/_authors.de.html.erb
+++ b/app/views/shared/_authors.de.html.erb
@@ -1,5 +1,5 @@
 <% if authors.empty? %>
-  Diese Übersetung wurde anonym erstellt.
+  Diese Übersetzung wurde anonym erstellt.
 <% else %>
   Diese Übersetzung wurde von
   <% if local_assigns[:has_anonymous_author] %>
diff --git a/config/locales/views/admin/de.yml b/config/locales/views/admin/de.yml
index 5dd9125..ecf07fe 100644
--- a/config/locales/views/admin/de.yml
+++ b/config/locales/views/admin/de.yml
@@ -21,6 +21,7 @@ de:
         visit_current_translation: "Aktuelle Übersetzung anschauen"
         already_translated: "Dieses Problem wurde bereits übersetzt."
         is_new_translation: "Dieses Problem hat bisher keine Übersetzung."
+        changed_title_html: "Neuer Titel: <code>%{new}</code> statt <code>%{old}</code>"
       accept:
         success_message: "Übersetzung wurde erfolgreich akzeptiert!"
       decline:
diff --git a/config/locales/views/application/de.yml b/config/locales/views/application/de.yml
index 3f4896d..d4b0076 100644
--- a/config/locales/views/application/de.yml
+++ b/config/locales/views/application/de.yml
@@ -6,8 +6,9 @@ de:
     updated_at: Aktualisiert
   application:
     site_title: "Projekt Euler"
-    sign_in: 'Einloggen'
-    sign_out: 'Ausloggen'
+    sign_in_with_github: 'Mit GitHub anmelden'
+    logged_in_as_html: "Angemeldet als <b>%{name}</b>"
+    sign_out: 'Abmelden'
     info: "Info"
     privacy: "Datenschutz"
     legal: "Impressum"
diff --git a/db/seeds.rb b/db/seeds.rb
index 6a36b07..f7c26d6 100644
--- a/db/seeds.rb
+++ b/db/seeds.rb
@@ -10,13 +10,27 @@ Translation.delete_all
 Problem.delete_all
 User.delete_all
 
+admin = User.create!(
+    provider: :developer,
+    uid: "admin",
+    name: "admin",
+    role: :admin
+)
 
-for i in 1..20 do
+translator = User.create!(
+    provider: :developer,
+    uid: "translator",
+    name: "translator",
+    role: :user
+)
+
+for i in 1..60 do
   Problem.create!(id: i)
 end
 
 for i in 1..10 do
   translation = Translation.create!(
+   author: translator,
    problem: Problem.find(i),
    title: "Problem Nummer #{i}",
    content: %Q(<p>Das hier ist der Inhalt von <b>Problem #{i}</b>.
@@ -30,19 +44,6 @@ for i in 1..10 do
 end
 
 
-User.create!(
-  provider: :developer,
-  uid: "admin",
-  name: "admin",
-  role: 1
-)
-
-User.create!(
-  provider: :developer,
-  uid: "translator",
-  name: "translator"
-)
-
 p "Created #{Problem.count} problems"
 p "Created #{Translation.count} translations"
 p "Created #{User.count} users"