diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index ccc28ebc..1f9a97bc 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -21,14 +21,20 @@ ones are marked like "v1.0.0-fork".
 
 ### Fixed
 
-* Fixes [#113](https://github.com/HugoFara/lwt/issues/113): changing a language name was making text-to-speech unusable and may prompt a warning.
-* Since 2.9.0, tests may be unable to run due to a missing key in an AJAX request ("type"). This is fixed.
+* Fixes [#113](https://github.com/HugoFara/lwt/issues/113): changing a language name 
+was making text-to-speech unusable and may prompt a warning.
+* Since 2.9.0, tests may be unable to run due to a missing key in an AJAX request ("type").
 * Since 2.9.0, audio position was not saved properly.
 * On `upload_words.php`, "update only empty fields" was broken.
 * Translation were not set by default properly when editing terms translations table.
 * The field MeCab was set for japanese even when not asked for. 
-Signalled on PR [#155](https://github.com/HugoFara/lwt/pull/155), thanks to [@ProgramComputer](https://github.com/ProgramComputer).
-* Since 2.8.1, japanese word romanization was not displayed any more. Thanks to 아르노 for signalling the bug on Discord!
+Signalled on PR [#155](https://github.com/HugoFara/lwt/pull/155), thanks to 
+[@ProgramComputer](https://github.com/ProgramComputer).
+* Since 2.8.1, japanese word romanization was not displayed any more. 
+Thanks to 아르노 for signalling the bug on Discord!
+* The go slower/faster feature on audio was broken 
+([#138](https://github.com/HugoFara/lwt/issues/138)), as functions `click_slower` 
+and `click_faster` were declared two times in `src/js/audio_controller.js`.
 
 ### Deprecated
 
diff --git a/docs/info.html b/docs/info.html
index 075c6880..af978aaa 100644
--- a/docs/info.html
+++ b/docs/info.html
@@ -2200,14 +2200,20 @@ <h4>Changed</h4>
 </ul>
 <h4>Fixed</h4>
 <ul>
-<li>Fixes <a href="https://github.com/HugoFara/lwt/issues/113">#113</a>: changing a language name was making text-to-speech unusable and may prompt a warning.</li>
-<li>Since 2.9.0, tests may be unable to run due to a missing key in an AJAX request ("type"). This is fixed.</li>
+<li>Fixes <a href="https://github.com/HugoFara/lwt/issues/113">#113</a>: changing a language name
+was making text-to-speech unusable and may prompt a warning.</li>
+<li>Since 2.9.0, tests may be unable to run due to a missing key in an AJAX request ("type").</li>
 <li>Since 2.9.0, audio position was not saved properly.</li>
 <li>On <code>upload_words.php</code>, "update only empty fields" was broken.</li>
 <li>Translation were not set by default properly when editing terms translations table.</li>
 <li>The field MeCab was set for japanese even when not asked for.
-Signalled on PR <a href="https://github.com/HugoFara/lwt/pull/155">#155</a>, thanks to <a href="https://github.com/ProgramComputer">@ProgramComputer</a>.</li>
-<li>Since 2.8.1, japanese word romanization was not displayed any more. Thanks to 아르노 for signalling the bug on Discord!</li>
+Signalled on PR <a href="https://github.com/HugoFara/lwt/pull/155">#155</a>, thanks to
+<a href="https://github.com/ProgramComputer">@ProgramComputer</a>.</li>
+<li>Since 2.8.1, japanese word romanization was not displayed any more.
+Thanks to 아르노 for signalling the bug on Discord!</li>
+<li>The go slower/faster feature on audio was broken
+(<a href="https://github.com/HugoFara/lwt/issues/138">#138</a>), as functions <code>click_slower</code>
+and <code>click_faster</code> were declared two times in <code>src/js/audio_controller.js</code>.</li>
 </ul>
 <h4>Deprecated</h4>
 <ul>
diff --git a/inc/session_utility.php b/inc/session_utility.php
index e69c18e3..f4bd12fd 100644
--- a/inc/session_utility.php
+++ b/inc/session_utility.php
@@ -5184,13 +5184,18 @@ function addjPlayerMedia () {
         if ($('#jquery_jplayer_1').data().jPlayer.status.playbackRateEnabled) {
             $("#playbackrateContainer").css("margin-top",".2em")
             .html(
-                `<span id="pbSlower" style="position:absolute;top: 0; left: 0; bottom: 0; right: 50%;" title="Slower" onclick="click_slower();">
+                `<span id="pbSlower" 
+                style="position:absolute;top: 0; left: 0; bottom: 0; right: 50%;" 
+                title="Slower" onclick="lwt_audio_controller.clickSlower();">
                     &nbsp;
                 </span>
-                <span id="pbFaster" style="position:absolute;top: 0; left: 50%; bottom: 0; right: 0;" title="Faster" onclick="click_faster();">
+                <span id="pbFaster" 
+                style="position:absolute;top: 0; left: 50%; bottom: 0; right: 0;" 
+                title="Faster" onclick="lwt_audio_controller.clickFaster();">
                     &nbsp;
                 </span>
-                <span class="ui-widget ui-state-default ui-corner-all" style="padding-left: 0.2em;padding-right: 0.2em;color:grey">
+                <span class="ui-widget ui-state-default ui-corner-all" 
+                style="padding-left: 0.2em;padding-right: 0.2em;color:grey">
                     <span id="playbackSlower" style="padding-right: 0.15em;">≪</span>
                     <span id="pbvalue">1.0</span>
                     <span id="playbackFaster" style="padding-left: 0.15em;">≫</span>
@@ -5228,9 +5233,9 @@ function prepareMediaInteractions() {
             set_current_playbackrate();
         });
         
-        $("#slower").on('click', click_slower);
-        $("#faster").on('click', click_faster);
-        $("#stdspeed").on('click', click_stdspeed);
+        $("#slower").on('click', lwt_audio_controller.setSlower);
+        $("#faster").on('click', lwt_audio_controller.setFaster);
+        $("#stdspeed").on('click', lwt_audio_controller.setStdSpeed);
         $("#backbutt").on('click', click_back);
         $("#forwbutt").on('click', click_forw);
         $("#do-single").on('click', click_single);
diff --git a/js/pgm.js b/js/pgm.js
index dd326a59..eeb7e823 100644
--- a/js/pgm.js
+++ b/js/pgm.js
@@ -3,10 +3,10 @@
  * 
  * @license Unlicense
  */
-const lwt_audio_controller={newPosition:function(position){$("#jquery_jplayer_1").jPlayer("playHead",position)},setNewPlayerseconds:function(){const newval=$("#backtime :selected").val();do_ajax_save_setting('currentplayerseconds',newval)},setNewPlaybackrate:function(){const newval=$("#playbackrate :selected").val();do_ajax_save_setting('currentplaybackrate',newval);$("#jquery_jplayer_1").jPlayer("option","playbackRate",newval*0.1)},setCurrentPlaybackrate:function(){const val=$("#playbackrate :selected").val();$("#jquery_jplayer_1").jPlayer("option","playbackRate",val*0.1)},clickSingle:function(){$("#jquery_jplayer_1").off('bind',$.jPlayer.event.ended+".jp-repeat");$("#do-single").addClass('hide');$("#do-repeat").removeClass('hide');do_ajax_save_setting('currentplayerrepeatmode','0');return!1},clickRepeat:function(){$("#jquery_jplayer_1").on('bind',$.jPlayer.event.ended+".jp-repeat",function(_event){$(this).jPlayer("play")});$("#do-repeat").addClass('hide');$("#do-single").removeClass('hide');do_ajax_save_setting('currentplayerrepeatmode','1');return!1},clickBack:function(){const t=parseInt($("#playTime").text(),10);const b=parseInt($("#backtime").val(),10);let nt=t-b;let st='pause';if(nt<0)
+const lwt_audio_controller={newPosition:function(position){$("#jquery_jplayer_1").jPlayer("playHead",position)},setNewPlayerseconds:function(){const newval=$("#backtime :selected").val();do_ajax_save_setting('currentplayerseconds',newval)},setNewPlaybackRate:function(){const newval=$("#playbackrate :selected").val();do_ajax_save_setting('currentplaybackrate',newval);$("#jquery_jplayer_1").jPlayer("option","playbackRate",newval*0.1)},setCurrentPlaybackrate:function(){const val=$("#playbackrate :selected").val();$("#jquery_jplayer_1").jPlayer("option","playbackRate",val*0.1)},clickSingle:function(){$("#jquery_jplayer_1").off('bind',$.jPlayer.event.ended+".jp-repeat");$("#do-single").addClass('hide');$("#do-repeat").removeClass('hide');do_ajax_save_setting('currentplayerrepeatmode','0');return!1},clickRepeat:function(){$("#jquery_jplayer_1").on('bind',$.jPlayer.event.ended+".jp-repeat",function(_event){$(this).jPlayer("play")});$("#do-repeat").addClass('hide');$("#do-single").removeClass('hide');do_ajax_save_setting('currentplayerrepeatmode','1');return!1},clickBack:function(){const t=parseInt($("#playTime").text(),10);const b=parseInt($("#backtime").val(),10);let nt=t-b;let st='pause';if(nt<0)
 nt=0;if(!$('#jquery_jplayer_1').data().jPlayer.status.paused)
 st='play';$("#jquery_jplayer_1").jPlayer(st,nt)},clickForward:function(){const t=parseInt($("#playTime").text(),10);const b=parseInt($("#backtime").val(),10);const nt=t+b;let st='pause';if(!$('#jquery_jplayer_1').data().jPlayer.status.paused)
-st='play';$("#jquery_jplayer_1").jPlayer(st,nt)},clickSlower:function(){const val=parseFloat($("#pbvalue").text())-0.1;if(val>=0.5){$("#pbvalue").text(val.toFixed(1)).css({'color':'#BBB'}).animate({color:'#888'},150,function(){});$("#jquery_jplayer_1").jPlayer("playbackRate",val)}},clickFaster:function(){const val=parseFloat($("#pbvalue").text())+0.1;if(val<=4.0){$("#pbvalue").text(val.toFixed(1)).css({'color':'#BBB'}).animate({color:'#888'},150,function(){});$("#jquery_jplayer_1").jPlayer("playbackRate",val)}},clickStdSpeed:function(){$("#playbackrate").val(10);this.setNewPlaybackRate()},clickSlower:function(){let val=$("#playbackrate :selected").val();if(val>5){val--;$("#playbackrate").val(val);this.setNewPlaybackRate()}},clickFaster:function(){let val=$("#playbackrate :selected").val();if(val<15){val++;$("#playbackrate").val(val);this.setNewPlaybackRate()}},}
+st='play';$("#jquery_jplayer_1").jPlayer(st,nt)},clickSlower:function(){const val=parseFloat($("#pbvalue").text())-0.1;if(val>=0.5){$("#pbvalue").text(val.toFixed(1)).css({'color':'#BBB'}).animate({color:'#888'},150,function(){});$("#jquery_jplayer_1").jPlayer("playbackRate",val)}},clickFaster:function(){const val=parseFloat($("#pbvalue").text())+0.1;if(val<=4.0){$("#pbvalue").text(val.toFixed(1)).css({'color':'#BBB'}).animate({color:'#888'},150,function(){});$("#jquery_jplayer_1").jPlayer("playbackRate",val)}},setStdSpeed:function(){$("#playbackrate").val(10);lwt_audio_controller.setNewPlaybackRate()},setSlower:function(){let val=$("#playbackrate :selected").val();if(val>5){val--;$("#playbackrate").val(val);lwt_audio_controller.setNewPlaybackRate()}},setFaster:function(){let val=$("#playbackrate :selected").val();if(val<15){val++;$("#playbackrate").val(val);lwt_audio_controller.setNewPlaybackRate()}},}
 function new_pos(p){return lwt_audio_controller.newPosition(p)}
 function set_new_playerseconds(){return lwt_audio_controller.setNewPlayerseconds()}
 function set_new_playbackrate(){return lwt_audio_controller.setNewPlaybackrate()}
@@ -17,9 +17,9 @@ function click_back(){return lwt_audio_controller.clickBack()}
 function click_forw(){return lwt_audio_controller.clickForward()}
 function click_slower(){return lwt_audio_controller.clickSlower()}
 function click_faster(){return lwt_audio_controller.clickFaster()}
-function click_stdspeed(){return lwt_audio_controller.clickStdSpeed()}
-function click_slower(){return lwt_audio_controller.clickSlower()}
-function click_faster(){return lwt_audio_controller.clickFaster()};function CountUp(server_now,server_start,id,dontrun){if(server_now<server_start)server_start=server_now;this.beginSecs=Math.floor(((new Date()).getTime())/1000)-server_now+server_start;this.dontrun=dontrun;this.update(id)}
+function click_stdspeed(){return lwt_audio_controller.setStdSpeed()}
+function click_slower(){return lwt_audio_controller.setSlower()}
+function click_faster(){return lwt_audio_controller.setFaster()};function CountUp(server_now,server_start,id,dontrun){if(server_now<server_start)server_start=server_now;this.beginSecs=Math.floor(((new Date()).getTime())/1000)-server_now+server_start;this.dontrun=dontrun;this.update(id)}
 CountUp.prototype.update=function(id){var nowSecs=Math.floor(((new Date()).getTime())/1000);var sec=nowSecs-this.beginSecs;var min=Math.floor(sec/60);sec=sec-min*60;var hr=Math.floor(min/60);min=min-hr*60;var r='';if(hr>0){r+=hr<10?("0"+hr):hr;r+=":"}
 r+=min<10?("0"+min):min;r+=":";r+=sec<10?("0"+sec):sec;document.getElementById(id).innerHTML=r;if(this.dontrun)return;var self=this;setTimeout(function(){self.update(id)},1000)};/**
  * Control the interactions for making an automated feed wizard.
diff --git a/src/js/audio_controller.js b/src/js/audio_controller.js
index 7767b66b..64048d1b 100644
--- a/src/js/audio_controller.js
+++ b/src/js/audio_controller.js
@@ -23,7 +23,7 @@ const lwt_audio_controller = {
         do_ajax_save_setting('currentplayerseconds', newval);
     },
 
-    setNewPlaybackrate: function () {
+    setNewPlaybackRate: function () {
         const newval = $("#playbackrate :selected").val();
         do_ajax_save_setting('currentplaybackrate', newval); 
         $("#jquery_jplayer_1").jPlayer("option","playbackRate", newval * 0.1);
@@ -93,26 +93,26 @@ const lwt_audio_controller = {
         }
     },
 
-    clickStdSpeed: function () {
+    setStdSpeed: function () {
         $("#playbackrate").val(10);
-        this.setNewPlaybackRate();
+        lwt_audio_controller.setNewPlaybackRate();
     },
 
-    clickSlower: function () {
+    setSlower: function () {
         let val = $("#playbackrate :selected").val();
         if (val > 5) {
             val--;
             $("#playbackrate").val(val);
-            this.setNewPlaybackRate();
+            lwt_audio_controller.setNewPlaybackRate();
         }
     },
 
-    clickFaster: function () {
+    setFaster: function () {
         let val = $("#playbackrate :selected").val();
         if (val < 15) {
             val++;
             $("#playbackrate").val(val);
-            this.setNewPlaybackRate();
+            lwt_audio_controller.setNewPlaybackRate();
         }
     },
 
@@ -166,13 +166,13 @@ function click_faster() {
 }
 
 function click_stdspeed() {
-    return lwt_audio_controller.clickStdSpeed();
+    return lwt_audio_controller.setStdSpeed();
 }
 
 function click_slower() {
-    return lwt_audio_controller.clickSlower();
+    return lwt_audio_controller.setSlower();
 }
 
 function click_faster() {
-    return lwt_audio_controller.clickFaster();
+    return lwt_audio_controller.setFaster();
 }