diff --git a/.gitignore b/.gitignore
index b7e7725..3476aa5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,4 +7,5 @@
 /pkg/
 /spec/reports/
 /tmp/
+/bin/
 *.gem
diff --git a/.rubocop.yml b/.rubocop.yml
index c796613..d60d44a 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -16,6 +16,10 @@ Style/Documentation:
 Style/FileName:
   Enabled: false
 
+Style/IndentHeredoc:
+  Exclude:
+    - spec/**/*
+
 AllCops:
   Exclude:
     - vendor/**/*
diff --git a/Gemfile b/Gemfile
index 0919f4a..c626203 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,15 +1,15 @@
-source 'https://rubygems.org'
-require 'json'
-require 'open-uri'
+source "https://rubygems.org"
+require "json"
+require "open-uri"
 
 gemspec
 
 group :development, :test do
-  versions = JSON.parse(open('https://pages.github.com/versions.json').read)
-  versions.delete('ruby')
-  versions.delete('jekyll-seo-tag')
-  versions.delete('github-pages')
-  versions.delete('jekyll') # Remove this line when GitHub Pages supports 3.3.0
+  versions = JSON.parse(open("https://pages.github.com/versions.json").read)
+  versions.delete("ruby")
+  versions.delete("jekyll-seo-tag")
+  versions.delete("github-pages")
+  versions.delete("jekyll") # Remove this line when GitHub Pages supports 3.3.0
 
   versions.each do |dep, version|
     gem dep, version
diff --git a/README.md b/README.md
index 8f71d58..ddcd9a0 100644
--- a/README.md
+++ b/README.md
@@ -13,8 +13,8 @@ Jekyll SEO Tag adds the following meta tags to your site:
 * Canonical URL
 * Next and previous URLs on paginated pages
 * [JSON-LD Site and post metadata](https://developers.google.com/structured-data/) for richer indexing
-* [Open graph](http://ogp.me/) title, description, site title, and URL (for Facebook, LinkedIn, etc.)
-* [Twitter summary card](https://dev.twitter.com/cards/overview) metadata
+* [Open Graph](http://ogp.me/) title, description, site title, and URL (for Facebook, LinkedIn, etc.)
+* [Twitter Summary Card](https://dev.twitter.com/cards/overview) metadata
 
 While you could theoretically add the necessary metadata tags yourself, Jekyll SEO Tag provides a battle-tested template of crowdsourced best-practices.
 
@@ -102,12 +102,15 @@ webmaster_verifications:
   yandex: 1234
 ```
 
+* `lang` - The locale these tags are marked up in. Of the format `language_TERRITORY`. Default is `en_US`.
+
 The SEO tag will respect the following YAML front matter if included in a post, page, or document:
 
 * `title` - The title of the post, page, or document
 * `description` - A short description of the page's content
 * `image` - URL to an image associated with the post, page, or document (e.g., `/assets/page-pic.jpg`)
 * `author` - Page-, post-, or document-specific author information (see below)
+* `lang` - Page-, post-, or document-specific language information
 
 ## Advanced usage
 
@@ -191,17 +194,14 @@ The following options can be set for any particular page. While the default opti
 For most users, setting `image: [path-to-image]` on a per-page basis should be enough. If you need more control over how images are represented, the `image` property can also be an object, with the following options:
 
 * `path` - The relative path to the image. Same as `image: [path-to-image]`
-* `twitter` - The relative path to a Twitter-specific image.
-* `facebook` - The relative path to a Facebook-specific image.
-* `height` - The height of the Facebook (`og:image`) image
-* `width` - The width of the Facebook (`og:image`) image
+* `height` - The height of the Open Graph (`og:image`) image
+* `width` - The width of the Open Graph (`og:image`) image
 
 You can use any of the above, optional properties, like so:
 
 ```yml
 image:
-  twitter: /img/twitter.png
-  facebook: /img/facebook.png
+  path: /img/twitter.png
   height: 100
   width: 100
 ```
diff --git a/Rakefile b/Rakefile
index 4c774a2..b7e9ed5 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,6 +1,6 @@
-require 'bundler/gem_tasks'
-require 'rspec/core/rake_task'
+require "bundler/gem_tasks"
+require "rspec/core/rake_task"
 
 RSpec::Core::RakeTask.new(:spec)
 
-task default: :spec
+task :default => :spec
diff --git a/lib/jekyll-seo-tag.rb b/lib/jekyll-seo-tag.rb
index 696daa6..7d3a736 100644
--- a/lib/jekyll-seo-tag.rb
+++ b/lib/jekyll-seo-tag.rb
@@ -44,7 +44,7 @@ module Jekyll
     end
 
     def title?
-      !(@text =~ %r!title=false!i)
+      @text !~ %r!title=false!i
     end
 
     def info
diff --git a/lib/template.html b/lib/template.html
index eacff7f..c06665c 100755
--- a/lib/template.html
+++ b/lib/template.html
@@ -90,13 +90,15 @@
 {% endif %}
 
 {% if page.image %}
-  {% assign seo_page_image = page.image.path | default: page.image.facebook | default: page.image %}
+  {% assign seo_page_image = page.image.path | default: page.image.facebook | default: page.image.twitter | default: page.image %}
   {% unless seo_page_image contains "://" %}
     {% assign seo_page_image = seo_page_image | absolute_url %}
   {% endunless %}
   {% assign seo_page_image = seo_page_image | escape %}
 {% endif %}
 
+{% assign seo_page_lang = page.lang | default: site.lang | default: "en_US" %}
+
 {% if seo_tag.title and seo_title %}
   <title>{{ seo_title }}</title>
 {% endif %}
@@ -109,6 +111,8 @@
   <meta name="author" content="{{ seo_author_name }}" />
 {% endif %}
 
+<meta property="og:locale" content="{{ seo_page_lang | replace:'-','_' }}" />
+
 {% if seo_description %}
   <meta name="description" content="{{ seo_description }}" />
   <meta property="og:description" content="{{ seo_description }}" />
@@ -124,7 +128,7 @@
 {% endif %}
 
 {% if seo_page_image %}
-<meta property="og:image" content="{{ seo_page_image }}" />
+  <meta property="og:image" content="{{ seo_page_image }}" />
   {% if page.image.height %}
     <meta property="og:image:height" content="{{ page.image.height }}" />
   {% endif %}
@@ -133,10 +137,6 @@
   {% endif %}
 {% endif %}
 
-{% if page.image.twitter %}
-  <meta name="twitter:image" content="{{ page.image.twitter | absolute_url }}" />
-{% endif %}
-
 {% if page.date %}
   <meta property="og:type" content="article" />
   <meta property="article:published_time" content="{{ page.date | date_to_xmlschema }}" />
diff --git a/spec/jekyll_seo_tag_spec.rb b/spec/jekyll_seo_tag_spec.rb
index 1937ab9..e2bcb0b 100755
--- a/spec/jekyll_seo_tag_spec.rb
+++ b/spec/jekyll_seo_tag_spec.rb
@@ -172,7 +172,7 @@ describe Jekyll::SeoTag do
     context "with relative page.image as a string" do
       let(:page) { make_page("image" => "/img/foo.png") }
 
-      it "outputs the image" do
+      it "outputs an open graph image" do
         expected = '<meta property="og:image" content="http://example.invalid/img/foo.png" />'
         expect(output).to include(expected)
       end
@@ -181,7 +181,7 @@ describe Jekyll::SeoTag do
     context "with absolute page.image" do
       let(:page) { make_page("image" => "http://cdn.example.invalid/img/foo.png") }
 
-      it "outputs the image" do
+      it "outputs an open graph image" do
         expected = '<meta property="og:image" content="http://cdn.example.invalid/img/foo.png" />'
         expect(output).to include(expected)
       end
@@ -191,7 +191,7 @@ describe Jekyll::SeoTag do
       context "when given a path" do
         let(:page) { make_page("image" => { "path" => "/img/foo.png" }) }
 
-        it "outputs the image" do
+        it "outputs an open graph image" do
           expected = %r!<meta property="og:image" content="http://example.invalid/img/foo.png" />!
           expect(output).to match(expected)
         end
@@ -200,7 +200,7 @@ describe Jekyll::SeoTag do
       context "when given a facebook image" do
         let(:page) { make_page("image" => { "facebook" => "/img/facebook.png" }) }
 
-        it "outputs the image" do
+        it "outputs an open graph image" do
           expected = %r!<meta property="og:image" content="http://example.invalid/img/facebook.png" />!
           expect(output).to match(expected)
         end
@@ -209,17 +209,17 @@ describe Jekyll::SeoTag do
       context "when given a twitter image" do
         let(:page) { make_page("image" => { "twitter" => "/img/twitter.png" }) }
 
-        it "outputs the image" do
-          expected = %r!<meta name="twitter:image" content="http://example.invalid/img/twitter.png" />!
+        it "outputs an open graph image" do
+          expected = %r!<meta property="og:image" content="http://example.invalid/img/twitter.png" />!
           expect(output).to match(expected)
         end
       end
 
-      context "when given the image height and width" do
-        let(:image) { { "facebook" => "/img/foo.png", "height" => 1, "width" => 2 } }
+      context "when given an image height and width" do
+        let(:image) { { "path" => "/img/foo.png", "height" => 1, "width" => 2 } }
         let(:page) { make_page("image" => image) }
 
-        it "outputs the image" do
+        it "outputs an open graph image width and height" do
           expected = %r!<meta property="og:image:height" content="1" />!
           expect(output).to match(expected)
           expected = %r!<meta property="og:image:width" content="2" />!
@@ -257,6 +257,7 @@ describe Jekyll::SeoTag do
 <!-- Begin Jekyll SEO tag v#{version} -->
 <title>Foo</title>
 <meta property="og:title" content="Foo" />
+<meta property="og:locale" content="en_US" />
 <link rel="canonical" href="http://example.invalid/page.html" />
 <meta property="og:url" content="http://example.invalid/page.html" />
 <meta property="og:site_name" content="Foo" />
@@ -581,4 +582,38 @@ EOS
       end
     end
   end
+
+  context "with locale" do
+    it "uses en_US when no locale is specified" do
+      expected = %r!<meta property="og:locale" content="en_US" />!
+      expect(output).to match(expected)
+    end
+
+    context "with site.lang" do
+      let(:site)  { make_site("lang" => "en_US") }
+
+      it "uses site.lang if page.lang is not present" do
+        expected = %r!<meta property="og:locale" content="en_US" />!
+        expect(output).to match(expected)
+      end
+
+      context "with page.lang" do
+        let(:page)  { make_page("lang" => "en_UK") }
+
+        it "uses page.lang if both site.lang and page.lang are present" do
+          expected = %r!<meta property="og:locale" content="en_UK" />!
+          expect(output).to match(expected)
+        end
+      end
+    end
+
+    context "with site.lang hyphenated" do
+      let(:site)  { make_site("lang" => "en-US") }
+
+      it "coerces hyphen to underscore" do
+        expected = %r!<meta property="og:locale" content="en_US" />!
+        expect(output).to match(expected)
+      end
+    end
+  end
 end