diff --git a/config/webpack.dev.conf.js b/config/webpack.dev.conf.js
new file mode 100644
index 000000000..d9b990e07
--- /dev/null
+++ b/config/webpack.dev.conf.js
@@ -0,0 +1,35 @@
+var webpack = require('webpack')
+
+module.exports = {
+  entry: './index.js',
+  output: {
+    path: './',
+    publicPath: '/',
+    filename: 'build.js'
+  },
+  devtool: 'source-map',
+  module: {
+    preLoaders: [{
+      test: /\.js$/,
+      exclude: /node_modules/,
+      loader: 'eslint-loader'
+    }],
+    loaders: [{
+      test: /\.js$/,
+      exclude: /node_modules|vue\/dist/,
+      loader: 'babel',
+      query: {
+        presets: ['es2015']
+      }
+    }]
+  },
+  devServer: {
+    contentBase: './',
+    port: 8080,
+    hot: true,
+    inline: true
+  },
+  plugins: [
+    new webpack.HotModuleReplacementPlugin()
+  ]
+}
diff --git a/package.json b/package.json
index 7fdf816fa..6bf5fd66c 100644
--- a/package.json
+++ b/package.json
@@ -51,7 +51,7 @@
     "rollup-plugin-babel": "^2.4.0",
     "rollup-plugin-replace": "^1.1.0",
     "uglify-js": "^2.6.1",
-    "vue": "^0.12.0",
+    "vue": "^1.0.21",
     "webpack": "^1.12.14",
     "webpack-dev-server": "^1.14.1"
   },
@@ -84,6 +84,7 @@
     "coolkids": "VUE_I18N_TYPE=sauce SAUCE=batch1 karma start config/karma.conf.js",
     "coverage": "VUE_I18N_TYPE=coverage karma start config/karma.conf.js",
     "coveralls": "VUE_I18N_TYPE=coveralls karma start config/karma.conf.js",
+    "proto": "webpack-dev-server --quite --config config/webpack.dev.conf.js --host 0.0.0.0",
     "dev": "webpack-dev-server --quiet --config config/webpack.test.conf.js",
     "e2e": "webpack-dev-server --quiet --config config/webpack.e2e.conf.js & mocha -t 20000 --compilers js:espower-babel/guess test/e2e/test.js && kill $! || (kill $! && exit 1)",
     "ie": "VUE_I18N_TYPE=sauce SAUCE=batch2 karma start config/karma.conf.js",
diff --git a/src/config.js b/src/config.js
new file mode 100644
index 000000000..73c4fecac
--- /dev/null
+++ b/src/config.js
@@ -0,0 +1,30 @@
+import { getWatcher, getDep } from './util'
+
+export default function (Vue, langVM) {
+  const Watcher = getWatcher(langVM)
+  const Dep = getDep(langVM)
+
+  function makeComputedGetter (getter, owner) {
+    let watcher = new Watcher(owner, getter, null, {
+      lazy: true
+    })
+
+    return function computedGetter () {
+      if (watcher.dirty) {
+        watcher.evaluate()
+      }
+      if (Dep.target) {
+        watcher.depend()
+      }
+      return watcher.value
+    }
+  }
+
+  // define Vue.config.lang configration
+  Object.defineProperty(Vue.config, 'lang', {
+    enumerable: true,
+    configurable: true,
+    get: makeComputedGetter(() => { return langVM.lang }, langVM),
+    set: Vue.util.bind((val) => { langVM.lang = val }, langVM)
+  })
+}
diff --git a/src/index.js b/src/index.js
index 2edf19082..c7370cdcb 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,5 +1,9 @@
-import util, { warn } from './util'
-import extend from './extend'
+import { warn } from './util'
+import Override from './override'
+import Config from './config'
+import Extend from './extend'
+
+let langVM // singleton
 
 
 /**
@@ -15,26 +19,20 @@ function plugin (Vue, opts = { lang: 'en', locales: {} }) {
     return
   }
 
-  defineConfig(Vue.config, opts.lang)
-  extend(Vue, opts.locales)
-}
-
+  setupLangVM(Vue, opts.lang)
 
-/**
- * defineConfig
- *
- * This function define `lang` property to `Vue.config`.
- *
- * @param {Object} config
- * @param {String} lang
- * @private
- */
+  Override(Vue, langVM)
+  Config(Vue, langVM)
+  Extend(Vue, opts.locales)
+}
 
-function defineConfig (config, lang) {
-  Object.defineProperty(config, 'lang', {
-    get: () => { return lang },
-    set: (val) => { lang = val }
-  })
+function setupLangVM (Vue, lang) {
+  const silent = Vue.config.silent
+  Vue.config.silent = true
+  if (!langVM) {
+    langVM = new Vue({ data: { lang: lang } })
+  }
+  Vue.config.silent = silent
 }
 
 plugin.version = '2.4.1'
diff --git a/src/override.js b/src/override.js
new file mode 100644
index 000000000..df359293b
--- /dev/null
+++ b/src/override.js
@@ -0,0 +1,40 @@
+export default function (Vue, langVM) {
+  // override _init
+  const init = Vue.prototype._init
+  Vue.prototype._init = function (options) {
+    options = options || {}
+    let root = options._parent || options.parent || this
+    let lang = root.$lang
+
+    if (lang) {
+      this.$lang = lang
+    } else {
+      this.$lang = langVM
+    }
+
+    this._langUnwatch = this.$lang.$watch('lang', (a, b) => {
+      update(this)
+    })
+
+    init.call(this, options)
+  }
+
+  // override _destroy
+  const destroy = Vue.prototype._destroy
+  Vue.prototype._destroy = function () {
+    if (this._langUnwatch) {
+      this._langUnwatch()
+      this._langUnwatch = null
+    }
+
+    this.$lang = null
+    destroy.apply(this, arguments)
+  }
+}
+
+function update (vm) {
+  let i = vm._watchers.length
+  while (i--) {
+    vm._watchers[i].update(true) // shallow updates
+  }
+}
diff --git a/test/specs/i18n.js b/test/specs/i18n.js
index 879936ba2..2e2b158de 100644
--- a/test/specs/i18n.js
+++ b/test/specs/i18n.js
@@ -291,15 +291,21 @@ describe('i18n', () => {
     })
 
     context('ja', () => {
-      it('should translate with japanese', () => {
+      it('should translate with japanese', (done) => {
         Vue.config.lang = 'ja'
-        assert(vm.$t('message.hello') === locales.ja.message.hello)
+        Vue.nextTick(() => {
+          assert(vm.$t('message.hello') === locales.ja.message.hello)
+          done()
+        })
       })
 
       context('en', () => {
-        it('should translate with english', () => {
+        it('should translate with english', (done) => {
           Vue.config.lang = 'en'
-          assert(vm.$t('message.hello') === locales.en.message.hello)
+          Vue.nextTick(() => {
+            assert(vm.$t('message.hello') === locales.en.message.hello)
+            done()
+          })
         })
       })
     })