diff --git a/app/cache.js b/app/cache.js
new file mode 100644
index 0000000..8b4e2e2
--- /dev/null
+++ b/app/cache.js
@@ -0,0 +1,126 @@
+
+export /*abstract */class Cache {
+  /**
+   * @param {string} key
+   * @return {boolean}
+   * @author fenris
+   */
+  /*protected */has(key) {
+    throw (new Error('not implemented'));
+  }
+  
+  /**
+   * @param {string} key
+   * @return {any}
+   * @author fenris
+   */
+  /*protected */fetch(key) {
+    throw (new Error('not implemented'));
+  }
+  
+  /**
+   * @param {string} key
+   * @param {any} value
+   * @author fenris
+   */
+  /*protected */store(key, value) {
+    throw (new Error('not implemented'));
+  }
+  
+  /**
+   * @param {string} key
+   * @param {()=>Promise<any>} retrieve
+   * @return {Promise<any>}
+   * @author fenris
+   */
+  /*public */async get(key, retrieve) {
+    if (this.has(key)) {
+      const value = this.fetch(key);
+      return Promise.resolve(value);
+    } else {
+      const value = await retrieve();
+      this.store(key, value);
+      return Promise.resolve(value);
+    }
+  }
+}
+
+
+/**
+ * @author fenris
+ */
+class CacheNone extends Cache {
+  /**
+   * @author fenris
+   */
+  /*public */constructor() {
+    super();
+  }
+  
+  /**
+   * @author fenris
+   */
+  /*protected */has(key) {
+    return false;
+  }
+  
+  /**
+   * @author fenris
+   */
+  /*protected */fetch(key) {
+    throw (new Error('not possible'));
+  }
+  
+  /**
+   * @author fenris
+   */
+  /*protected */store(key, value) {
+  }
+}
+
+
+/**
+ * @author fenris
+ */
+export class CacheLocalstorage extends Cache {
+  /**
+   * @param {string} [corner] for separating the cache instance from others
+   * @author fenris
+   */
+  /*public */constructor(corner = null) {
+    super();
+    this.corner = corner;
+  }
+  
+  /**
+   * @author fenris
+   */
+  /*private */augmentKey(key) {
+    return ((this.corner === null) ? key : (this.corner + '/' + key));
+  }
+  
+  /**
+   * @author fenris
+   */
+  /*protected */has(key) {
+    return (window.localStorage.getItem(this.augmentKey(key)) !== null);
+  }
+  
+  /**
+   * @author fenris
+   */
+  /*protected */fetch(key) {
+    const valueRaw = window.localStorage.getItem(this.augmentKey(key));
+    const value = JSON.parse(valueRaw);
+    return value;
+  }
+  
+  /**
+   * @author fenris
+   */
+  /*protected */store(key, value) {
+    const valueRaw = JSON.stringify(value);
+    window.localStorage.setItem(this.augmentKey(key), valueRaw);
+  }
+}
+
diff --git a/app/file.js b/app/file.js
new file mode 100644
index 0000000..739a599
--- /dev/null
+++ b/app/file.js
@@ -0,0 +1,40 @@
+
+/**
+ * @param {string} path
+ * @return Promise<string>
+ * @todo use Util.fetch instead?
+ * @author fenris
+ */
+export async function read (path) {
+  return (
+    new Promise(
+      (resolve, reject) => {
+        let request = new XMLHttpRequest();
+        request.open('GET', '/' + path, true);
+        request.onreadystatechange = () => {
+          switch (request.readyState) {
+            case XMLHttpRequest.DONE: {
+              switch (request.status) {
+                case 0: {
+                  reject(new Error('XMLHttpRequest failed'));
+                  break;
+                }
+                default: {
+                  resolve(request.responseText);
+                  break;
+                }
+              }
+              break;
+            }
+            default: {
+              console.warn('unhandled readyState "' + request.readyState + '"');
+              break;
+            }
+          }
+        };
+        request.send(null);
+      }
+    )
+  );
+}
+
diff --git a/app/index.js b/app/index.js
index 15737e9..c8a2377 100644
--- a/app/index.js
+++ b/app/index.js
@@ -11,6 +11,7 @@ import _dompurify from 'dompurify'
 import keyboardjs from 'keyboardjs'
 
 import { ContinuousVoiceHandler, PushToTalkVoiceHandler, VADVoiceHandler, initVoice } from './voice'
+import {initialize as localizationInitialize, translate} from './loc';
 
 const dompurify = _dompurify(window)
 
@@ -1013,18 +1014,28 @@ function userToState () {
 var voiceHandler
 var testVoiceHandler
 
-initVoice(data => {
-  if (testVoiceHandler) {
-    testVoiceHandler.write(data)
-  }
-  if (!ui.client) {
-    if (voiceHandler) {
-      voiceHandler.end()
+function translateEverything() {
+}
+
+async function main() {
+  await localizationInitialize(navigator.language);
+  translateEverything();
+  initVoice(data => {
+    if (testVoiceHandler) {
+      testVoiceHandler.write(data)
     }
-    voiceHandler = null
-  } else if (voiceHandler) {
-    voiceHandler.write(data)
-  }
-}, err => {
-  log('Cannot initialize user media. Microphone will not work:', err)
-})
+    if (!ui.client) {
+      if (voiceHandler) {
+        voiceHandler.end()
+      }
+      voiceHandler = null
+    } else if (voiceHandler) {
+      voiceHandler.write(data)
+    }
+  }, err => {
+    log('Cannot initialize user media. Microphone will not work:', err)
+  })
+}
+
+main();
+
diff --git a/app/loc.js b/app/loc.js
new file mode 100644
index 0000000..1328dc6
--- /dev/null
+++ b/app/loc.js
@@ -0,0 +1,121 @@
+import {CacheLocalstorage} from './cache';
+import {read as fileRead} from './file';
+// import {Util} from 'util';
+
+
+/**
+ * the relative path to the directory containing the JSON localization files
+ * 
+ * @var {string}
+ * @author fenris
+ */
+var _directory = 'loc';
+
+
+/**
+ * the default language to use
+ * 
+ * @var {string}
+ * @author fenris
+ */
+var _languageDefault = null;
+
+
+/**
+ * the fallback language to use
+ * 
+ * @var {string}
+ * @author fenris
+ */
+var _languageFallback = null;
+
+
+/**
+ * @var {Cache}
+ * @author fenris
+ */
+var _cache = null;
+
+
+/**
+ * two level map with ISO-639-1 code as first key and translation id as second key
+ * 
+ * @var {Map<string,Map<string,string>>}
+ * @author fenris
+ */
+var _data = {};
+
+
+/**
+ * @param {string} language
+ * @return Promise<Map<string,string>>
+ * @author fenris
+ */
+async function retrieveData (language) {
+  const regexp = (new RegExp("^([a-z]{2})$"));
+  if (regexp.exec(language) === null) {
+    return Promise.reject(new Error('invalid language code "' + language + '"'));
+  } else {
+    const path = (_directory + '/' + language + '.json');
+    let content;
+    try {
+      content = await fileRead(path);
+    } catch (exception) {
+      return Promise.reject(new Error('could not load localization data for language "' + language + '": ' + error.toString()));
+    }
+    let data;
+    try {
+      data = JSON.parse(content);
+    } catch (exception) {
+      return Promise.reject(new Error('invalid JSON localization data for language "' + language + '": ' + exception.toString()));
+    }
+    return Promise.resolve(data);
+  }
+}
+
+
+/**
+ * @param {string} languageDefault
+ * @param {string} [languageFallback]
+ * @author fenris
+ */
+export async function initialize (languageDefault, languageFallback = 'en') {
+  _cache = new CacheLocalstorage('loc');
+  _languageFallback = languageFallback;
+  _languageDefault = languageDefault;
+  for (const language of [_languageFallback, _languageDefault]) {
+    if (_data.hasOwnProperty(language)) continue;
+    console.log('--', 'loading localization data for language "' + language + '" ...');
+    let data;
+    try {
+      data = await _cache.get(language, () => retrieveData(language));
+    } catch (exception) {
+      console.warn(exception.toString());
+    }
+    _data[language] = data;
+  }
+}
+
+
+/**
+ * gets a translation by its key for a specific language
+ * 
+ * @param {string} key
+ * @param {string} [languageChosen]
+ * @return {string}
+ * @author fenris
+ */
+export function translate (key, languageChosen = _languageDefault) {
+  let result = undefined;
+  for (const language of [languageChosen, _languageFallback]) {
+    if (_data.hasOwnProperty(language) && (_data[language] !== undefined) && _data[language].hasOwnProperty(key)) {
+      result = _data[language][key];
+      break;
+    }
+  }
+  if (result === undefined) {
+    result = ('{{' + key + '}}');
+  }
+  return result;
+}
+
diff --git a/tools/build b/tools/build
new file mode 100755
index 0000000..0430b43
--- /dev/null
+++ b/tools/build
@@ -0,0 +1,8 @@
+#!/usr/bin/env sh
+
+npm run build
+
+## loc
+mkdir -p dist/loc
+cp -ruv loc/* dist/loc/
+