diff --git a/emscripten/.gitignore b/emscripten/.gitignore
new file mode 100644
index 00000000..1188e3d9
--- /dev/null
+++ b/emscripten/.gitignore
@@ -0,0 +1,7 @@
+*.o
+*.out
+*.pkl
+espeakng_data_package.js
+glue.*
+espeakng.worker.*
+pthread-main.js
diff --git a/emscripten/COPYING b/emscripten/COPYING
new file mode 100644
index 00000000..94a9ed02
--- /dev/null
+++ b/emscripten/COPYING
@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
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+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.
diff --git a/emscripten/README.md b/emscripten/README.md
new file mode 100644
index 00000000..6809edb1
--- /dev/null
+++ b/emscripten/README.md
@@ -0,0 +1,131 @@
+# espeakng.js
+
+This port of
+[eSpeak-ng](https://github.com/espeak-ng/espeak-ng)
+to Javascript via
+[emscripten](http://emscripten.org)
+allows client-side text-to-speech synthesis in any browser
+supporting Web workers and the Web Audio API.
+
+* Version: 1.49.0
+* Date: 2016-10-27
+* License: the GNU General Public License, Version 3 (GPLv3)
+* Size: 3.0 MB (including all the voices)
+
+
+## Demo
+
+For an online demo, visit [this page](https://www.readbeyond.it/espeakng/).
+
+If you prefer a local demo, open the file `demo.html` in your browser.
+(Depending on your browser, you might need to serve it via a Web server.
+A simple way consists in calling `$ python -m SimpleHTTPServer 8000`
+and pointing your browser to `http://localhost:8000/demo.html`)
+
+
+## Usage
+
+1. Include `js/espeakng.js` in your HTML file:
+    
+    ```html
+    <script type="text/javascript" src="js/espeakng.js"></script>
+    ```
+
+2. Create a new `eSpeakNG` instance with the path of the worker (e.g., `espeakng.worker.js`) as the first argument.
+   You can supply a callback function that will be called once the worker is ready:
+
+    ```js
+    <script>
+      var espeakng = new eSpeakNG('js/espeakng.worker.js', function(){
+        // now you can use espeakng
+        ...
+      });
+    </script>
+    ```
+
+3. Functions exposed by the `eSpeakNG` object:
+
+    * `list_voices(cb(voices))`: obtain the list of available voices, passing it (`voices`) to the callback function `cb`
+    * `set_rate(value)`: set the rate of the synthesized speech, `value` must be an integer in `[80..450]`, default `175`
+    * `set_pitch(value)`: set the pitch of the synthesized speech, `value` must be an integer in `[0..99]`, default `50`
+    * `set_voice.apply(espeakng, voice)`: set the voice for synthesizing speech, `voice` must be the code string for the desired voice (e.g., `en`, `en-us`, `it`, etc.)
+    * `synthesize(text, cb(samples, events))`: synthesize the given string `text` and call the callback function `cb` when done, passing the generated audio samples (`samples`) and events (`events`)
+
+    See the file `demo.html` for details.
+
+
+## Download
+
+You can download pre-built JS files from the [Releases page](https://github.com/pettarin/espeak-ng/releases).
+
+TODO: add the compiled JS files to a public free CDN, and list the URL here.
+
+
+## Building
+
+1. Make sure you have `emscripten` [installed and activated](http://kripken.github.io/emscripten-site/docs/getting_started/downloads.html).
+
+2. Clone the repo and enter the `espeak-ng` directory:
+
+    ```bash
+    $ git clone https://github.com/espeak-ng/espeak-ng
+    $ cd espeak-ng
+    ```
+
+3. Compile `espeak-ng`:
+
+    ```bash
+    $ ./autogen.sh
+    $ ./configure --prefix=/usr --without-async --without-mbrola --without-sonic
+    $ make
+    ```
+
+4. Recompile `espeak-ng` with `emconfigure` and `emmake`: 
+
+    ```bash
+    $ emconfigure ./configure --prefix=/usr --without-async --without-mbrola --without-sonic
+    $ emmake make
+    ```
+
+    Note: the `emmake make` command currently exits
+    with the error `recipe for target 'phsource/phonemes.stamp' failed`,
+    but you can safely ignore it.
+    (TODO: fix this issue.)
+
+5. Enter the `emscripten` directory and compile the JS worker with `emmake`:
+
+    ```bash
+    $ cd emscripten
+    $ emmake make
+    ```
+
+6. The `js/` directory should contain the output JS files:
+    
+    * `espeakng.js`,
+    * `espeakng.worker.js`, and
+    * `espeakng.worker.data`.
+
+### Notes
+
+* If you want to build only a single voice, for example the English one,
+  run `$ make en` instead of `$ make` at step 3.
+  You can also build a subset of all the available voices,
+  by running (say) `$ make en && make it && make fr && make es`.
+  Note that `list_voices()` will still list all available voices,
+  but if you try using one that has not been compiled,
+  you will get a runtime error.
+  (TODO: fix this issue.)
+* The `-O3` optimization flag is passed to `emscripten` by default,
+  achieving a considerable reduction of the size of the generated JS worker.
+  If you want to omit it, for example for debug purposes,
+  just `$ export EM_DEBUG=1` before calling `emmake make` in step 5.
+* To remove intermediate files compiled by emscripten,
+  keeping only the JS worker files, run `$ emmake clean-intermediate`.
+* To remove all the files compiled by emscripten, run `$ emmake clean`.
+
+
+## Credits
+
+[Eitan Isaacson](https://blog.monotonous.org/) wrote the [original glue code](https://github.com/eeejay/espeak/tree/emscripten) for compiling eSpeak to Javascript via emscripten.
+
+[Alberto Pettarin](http://www.albertopettarin.it) adapted Eitan's files [to work with eSpeak-ng](https://github.com/pettarin/espeak-ng/tree/emscripten) and wrote this `README` file.
diff --git a/emscripten/espeakng_glue.cpp b/emscripten/espeakng_glue.cpp
new file mode 100644
index 00000000..da2edbb8
--- /dev/null
+++ b/emscripten/espeakng_glue.cpp
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2014-2016 Eitan Isaacson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <emscripten.h>
+#include "speak_lib.h"
+
+static int gSamplerate = 0;
+
+class eSpeakNGWorker {
+public:
+  eSpeakNGWorker() : rate(espeakRATE_NORMAL), pitch(50), current_voice(NULL) {
+    if (!gSamplerate) {
+      gSamplerate = espeak_Initialize(
+        AUDIO_OUTPUT_SYNCHRONOUS, 100, NULL, espeakINITIALIZE_DONT_EXIT);
+    }
+    samplerate = gSamplerate;
+    voices = espeak_ListVoices(NULL);
+  }
+
+  void synth_(const char* aText, void* aCallback) {
+    t_espeak_callback* cb = reinterpret_cast<t_espeak_callback*>(aCallback);
+    espeak_SetSynthCallback(cb);
+    espeak_SetParameter(espeakPITCH, pitch, 0);
+    espeak_SetParameter(espeakRATE, rate, 0);
+
+    if (current_voice)
+      espeak_SetVoiceByProperties(current_voice);
+    else
+      espeak_SetVoiceByName("default");
+
+    espeak_Synth(aText, 0, 0, POS_CHARACTER, 0, 0, NULL, NULL);
+
+    // Reset callback so other instances will work too.
+    espeak_SetSynthCallback(NULL);
+  }
+
+  void set_voice(
+        const char* aName,
+        const char* aLang,
+        unsigned char aGender=0,
+        unsigned char aAge=0,
+        unsigned char aVariant = 0
+    ) {
+    espeak_VOICE props = { 0 };
+    props.name = aName;
+    props.languages = aLang;
+    props.gender = aGender;
+    props.age = aAge;
+    props.variant = aVariant;
+    // This way we don't need to allocate the name/lang strings to the heap.
+    // Instead, we store the actual global voice.
+    espeak_SetVoiceByProperties(&props);
+    current_voice = espeak_GetCurrentVoice();
+  }
+
+  int getSizeOfEventStruct_() {
+    return sizeof(espeak_EVENT);
+  }
+
+  const espeak_VOICE** voices;
+  int samplerate;
+  int rate;
+  int pitch;
+
+private:
+  espeak_VOICE* current_voice;
+};
+
+#include <glue.cpp>
+
diff --git a/emscripten/espeakng_glue.idl b/emscripten/espeakng_glue.idl
new file mode 100644
index 00000000..6ea73317
--- /dev/null
+++ b/emscripten/espeakng_glue.idl
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2014-2016 Eitan Isaacson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>.
+ */
+
+interface espeak_VOICE {
+  [Const] attribute DOMString name;
+  readonly attribute byte[] languages;
+  [Const] attribute DOMString identifier;
+  attribute octet gender;
+  attribute octet age;
+  attribute octet variant;
+  attribute octet xx1;
+  attribute long score;
+  attribute any spare;
+};
+
+enum espeak_EVENT_TYPE {
+  "espeakEVENT_LIST_TERMINATED",
+  "espeakEVENT_WORD",
+  "espeakEVENT_SENTENCE",
+  "espeakEVENT_MARK",
+  "espeakEVENT_PLAY",
+  "espeakEVENT_END",
+  "espeakEVENT_MSG_TERMINATED",
+  "espeakEVENT_PHONEME",
+  "espeakEVENT_SAMPLERATE"
+};
+
+interface espeak_EVENT {
+  readonly attribute espeak_EVENT_TYPE type;
+  readonly attribute unsigned long unique_identifier;
+  readonly attribute long text_position;
+  readonly attribute long length;
+  readonly attribute long audio_position;
+  readonly attribute long sample;
+  readonly attribute any user_data;
+};
+
+interface eSpeakNGWorker {
+  void eSpeakNGWorker();
+  void synth_(DOMString aText, VoidPtr aCallback);
+  long getSizeOfEventStruct_();
+  void set_voice(DOMString aName, DOMString aLang, optional octet gender=0, optional octet age=0, optional octet aVariant=0);
+  [Const] attribute espeak_VOICE[] voices;
+  readonly attribute long samplerate;
+  attribute long rate;
+  attribute long pitch;
+};
diff --git a/emscripten/js/demo.js b/emscripten/js/demo.js
new file mode 100644
index 00000000..6ff73513
--- /dev/null
+++ b/emscripten/js/demo.js
@@ -0,0 +1,257 @@
+/*
+ * Copyright (C) 2014-2016 Eitan Isaacson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>.
+ */
+
+/* An audio node that can have audio chunks pushed to it */
+
+function PushAudioNode(context, start_callback, end_callback, buffer_size) {
+  this.context = context;
+  this.start_callback = start_callback;
+  this.end_callback = end_callback;
+  this.buffer_size = buffer_size || 4096;
+  this.samples_queue = [];
+  this.scriptNode = context.createScriptProcessor(this.buffer_size, 1, 1);
+  this.connected = false;
+  this.sinks = [];
+  this.startTime = 0;
+  this.closed = false;
+  this.track_callbacks = new Map();
+}
+
+PushAudioNode.prototype.push = function(chunk) {
+  if (this.closed) {
+    throw 'Cannot push more chunks after node was closed';
+  }
+  this.samples_queue.push(chunk);
+  if (!this.connected) {
+    if (!this.sinks.length) {
+      throw 'No destination set for PushAudioNode';
+    }
+    this._do_connect();
+  }
+}
+
+PushAudioNode.prototype.close = function() {
+  this.closed = true;
+}
+
+PushAudioNode.prototype.connect = function(dest) {
+  this.sinks.push(dest);
+  if (this.samples_queue.length) {
+    this._do_connect();
+  }
+}
+
+PushAudioNode.prototype._do_connect = function() {
+  if (this.connected) return;
+  this.connected = true;
+  for (var dest of this.sinks) {
+    this.scriptNode.connect(dest);
+  }
+  this.scriptNode.onaudioprocess = this.handleEvent.bind(this);
+}
+
+PushAudioNode.prototype.disconnect = function() {
+  this.scriptNode.onaudioprocess = null;
+  this.scriptNode.disconnect();
+  this.connected = false;
+}
+
+PushAudioNode.prototype.addTrackCallback = function(aTimestamp, aCallback) {
+  var callbacks = this.track_callbacks.get(aTimestamp) || [];
+  callbacks.push(aCallback);
+  this.track_callbacks.set(aTimestamp, callbacks);
+}
+
+PushAudioNode.prototype.handleEvent = function(evt) {
+  if (!this.startTime) {
+    this.startTime = evt.playbackTime;
+    if (this.start_callback) {
+      this.start_callback();
+    }
+  }
+
+  var currentTime = evt.playbackTime - this.startTime;
+  var playbackDuration = this.scriptNode.bufferSize / this.context.sampleRate;
+  for (var entry of this.track_callbacks) {
+    var timestamp = entry[0];
+    var callbacks = entry[1];
+    if (timestamp < currentTime) {
+      this.track_callbacks.delete(timestamp);
+    } else if (timestamp < currentTime + playbackDuration) {
+      for (var cb of callbacks) {
+        cb();
+      }
+      this.track_callbacks.delete(timestamp);
+    }
+  }
+
+  var offset = 0;
+  while (this.samples_queue.length && offset < evt.target.bufferSize) {
+    var chunk = this.samples_queue[0];
+    var to_copy = chunk.subarray(0, evt.target.bufferSize - offset);
+    if (evt.outputBuffer.copyToChannel) {
+      evt.outputBuffer.copyToChannel(to_copy, 0, offset);
+    } else {
+      evt.outputBuffer.getChannelData(0).set(to_copy, offset);
+    }
+    offset += to_copy.length;
+    chunk = chunk.subarray(to_copy.length);
+    if (chunk.length)
+      this.samples_queue[0] = chunk;
+    else
+      this.samples_queue.shift();
+  }
+
+  if (!this.samples_queue.length && this.closed) {
+    if (this.end_callback) {
+      this.end_callback(evt.playbackTime - this.startTime);
+    }
+    this.disconnect();
+  }
+}
+
+
+
+/* Code specific to the demo */
+
+var ctx = new (window.AudioContext || window.webkitAudioContext)();
+var tts;
+var pusher;
+var pusher_buffer_size = 4096;
+var chunkID = 0;
+
+function stop() {
+  console.log('Inside stop()');
+  if (pusher) {
+    console.log('  Calling pusher.disconnect...');
+    pusher.disconnect();
+    console.log('  Calling pusher.disconnect... done');
+    pusher = null;
+  }
+  console.log('Leaving stop()');
+} // end of stop()
+
+function speak() {
+  console.log('Inside speak()');
+
+  console.log('  Stopping...');
+  stop();
+  console.log('  Stopping... done');
+
+  console.log('  Setting rate...');
+  tts.set_rate(Number(document.getElementById('rate').value));
+  console.log('  Setting rate... done');
+  console.log('  Setting pitch...');
+  tts.set_pitch(Number(document.getElementById('pitch').value));
+  console.log('  Setting pitch... done');
+  console.log('  Setting voice...');
+  tts.set_voice.apply(tts, (document.getElementById('voice').value.split(',')));
+  console.log('  Setting voice... done');
+
+  var now = Date.now();
+  chunkID = 0;
+  
+  console.log('  Creating pusher...');
+  pusher = new PushAudioNode(
+    ctx,
+    function() {
+      //console.log('PushAudioNode started!', ctx.currentTime, pusher.startTime);
+    },
+    function() {
+      //console.log('PushAudioNode ended!', ctx.currentTime - pusher.startTime);
+    },
+    pusher_buffer_size
+  );
+  pusher.connect(ctx.destination);
+  console.log('  Creating pusher... done');
+
+  // actual synthesis
+  console.log('  Calling synthesize...');
+  tts.synthesize(
+    document.getElementById('texttospeak').value,
+    function cb(samples, events) {
+      //console.log('  Inside synt cb');
+      if (!samples) {
+        if (pusher) {
+          pusher.close();
+        }
+        return;
+      }
+      if (pusher) {
+        //console.log('  Pushing chunk ' + chunkID, Date.now());
+        pusher.push(new Float32Array(samples));
+        ++chunkID;
+      }
+      if (now) {
+        //console.log('  Latency:', Date.now() - now);
+        now = 0;
+      }
+      //console.log('  Leaving synt cb');
+    } // end of function cb
+  ); // end of tts.synthesize()
+  console.log('  Calling synthesize... done');
+  
+  console.log('Leaving speak()');
+} // end of speak()
+
+function resetPitch() {
+  document.getElementById('pitch').value = 50;
+}
+
+function resetRate() {
+  document.getElementById('rate').value = 175;
+}
+
+function resetVoice() {
+  document.getElementById('default-voice').selected = true;
+}
+
+function initializeDemo() {
+  console.log('Creating eSpeakNG instance...');
+  tts = new eSpeakNG(
+    'js/espeakng.worker.js',
+    function cb1() {
+      console.log('Inside cb1');
+      tts.list_voices(
+        function cb2(result) {
+          console.log('Inside cb2');
+          var sel = document.getElementById('voice');
+          var index = 0;
+          for (voice of result) {
+            for (lang of voice.languages) {
+              var opt = document.createElement('option');
+              opt.text = voice.name + ' (' + lang.name + ')';
+              opt.value = [voice.name, lang.name];
+              console.log('Adding voice: ' + opt.text);
+              sel.add(opt);
+              if (voice.name === 'default') {
+                opt.id = 'default-voice';
+                opt.selected = true;
+              }
+            }
+          }
+          console.log('Leaving cb2');
+        } // end of function cb2
+      );
+      console.log('Removing loading class...');
+      document.body.classList.remove('loading');
+      console.log('Removing loading class... done');
+      console.log('Leaving cb1');
+    } // end of function cb1
+  );
+  console.log('Creating eSpeakNG instance... done');
+}
diff --git a/emscripten/js/espeakng.js b/emscripten/js/espeakng.js
new file mode 100644
index 00000000..b0615bf8
--- /dev/null
+++ b/emscripten/js/espeakng.js
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2014-2016 Eitan Isaacson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>.
+ */
+
+function eSpeakNG(worker_path, ready_cb) {
+  this.worker = new Worker(worker_path);
+  this.ready = false;
+  this.worker.onmessage = function(e) {
+    if (e.data !== 'ready') {
+      return;
+    }
+    this.worker.onmessage = null;
+    this.worker.addEventListener('message', this);
+    this.ready = true;
+    if (ready_cb) {
+      ready_cb();
+    }
+  }.bind(this);
+}
+
+eSpeakNG.prototype.handleEvent = function (evt) {
+  var callback = evt.data.callback;
+  if (callback && this[callback]) {
+    this[callback].apply(this, evt.data.result);
+    if (evt.data.done) {
+      delete this[callback];
+    }
+    return;
+  }
+};
+
+function _createAsyncMethod(method) {
+  return function() {
+    var lastArg = arguments[arguments.length - 1];
+    var message = { method: method, args: Array.prototype.slice.call(arguments, 0) };
+    if (typeof lastArg == 'function') {
+      var callback = '_' + method + '_' + Math.random().toString().substring(2) +'_cb';
+      this[callback] = lastArg;
+      message.args.pop();
+      message.callback = callback;
+    }
+    this.worker.postMessage(message);
+  };
+}
+
+for (var method of [
+    'list_voices',
+    'get_rate',
+    'get_pitch',
+    'set_rate',
+    'set_pitch',
+    'set_voice',
+    'synthesize'
+    ]) {
+  eSpeakNG.prototype[method] = _createAsyncMethod(method);
+}
diff --git a/emscripten/post.js b/emscripten/post.js
new file mode 100644
index 00000000..bd4e4687
--- /dev/null
+++ b/emscripten/post.js
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2014-2016 Eitan Isaacson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>.
+ */
+
+eSpeakNGWorker.prototype.list_voices = function() {
+  var voices = [];
+  var i;
+  for (var voice = this.get_voices(i = 0); voice.ptr != 0; voice = this.get_voices(++i)) {
+    var v = {
+      name: voice.get_name(),
+      identifier: voice.get_identifier(),
+      languages: [],
+    }
+
+    var ii = 0;
+    var byte = voice.get_languages(ii);
+
+    function nullTerminatedString(offset) {
+      var str = '';
+      var index = offset;
+      var b = voice.get_languages(index++);
+      while (b != 0) {
+        str += String.fromCharCode(b);
+        b = voice.get_languages(index++);
+      }
+
+      return str;
+    }
+
+    while (byte != 0) {
+      var lang = { priority: byte, name: nullTerminatedString(++ii) }
+      v.languages.push(lang);
+      ii += lang.name.length + 1;
+      byte = voice.get_languages(ii);
+    }
+
+    voices.push(v);
+
+  }
+  return voices;
+};
+
+var eventTypes = [
+  'list_terminated',
+  'word',
+  'sentence',
+  'mark',
+  'play',
+  'end',
+  'msg_terminated',
+  'phoneme',
+  'samplerate'
+]
+
+eSpeakNGWorker.prototype.synthesize = function (aText, aCallback) {
+  var eventStructSize = this.getSizeOfEventStruct_();
+  function cb(ptr, length, events_pointer) {
+    var data = new Float32Array(length*2);
+    for (var i = 0; i < length; i++) {
+      data[i*2] = Math.max(-1, Math.min(1, getValue(ptr + i*2, 'i16') / 32768));
+      data[i*2+1] = data[i*2];
+    }
+    var events = [];
+    var ptr = events_pointer;
+    for (ev = wrapPointer(ptr, espeak_EVENT);
+         ev.get_type() != Module.espeakEVENT_LIST_TERMINATED;
+         ev = wrapPointer((ptr += eventStructSize), espeak_EVENT)) {
+      events.push({
+        type: eventTypes[ev.get_type()],
+        text_position: ev.get_text_position(),
+        word_length: ev.get_length(),
+        audio_position: ev.get_audio_position()
+      });
+    }
+    return aCallback(data, events) ? 1 : 0;
+  }
+
+  var fp = Runtime.addFunction(cb);
+  this.synth_(aText, fp);
+  Runtime.removeFunction(fp);
+};
+
+// Make this a worker
+
+if (typeof WorkerGlobalScope !== 'undefined') {
+  var worker;
+
+  Module.postRun.push(function () {
+    worker = new eSpeakNGWorker();
+    postMessage('ready');
+  });
+
+  onmessage = function(e) {
+    if (!worker) {
+      throw 'eSpeakNGWorker worker not initialized';
+    }
+    var args = e.data.args;
+    var message = { callback: e.data.callback, done: true };
+    if (e.data.method == 'synthesize') {
+      args.push(function(samples, events) {
+        postMessage(
+          { callback: e.data.callback,
+            result: [samples.buffer, events] }, [samples.buffer]);
+      });
+    }
+    message.result = [worker[e.data.method].apply(worker, args)];
+    if (e.data.callback)
+      postMessage(message);
+  }
+}
diff --git a/emscripten/pre.js b/emscripten/pre.js
new file mode 100644
index 00000000..9b65adf4
--- /dev/null
+++ b/emscripten/pre.js
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2014-2016 Eitan Isaacson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>.
+ */
+