minor prose fix

Author: danielweck

css3-speech/Overview.html

@@ -567,8 +567,8 @@ <h3 id=mixing-props-voice-volume><span class=secno>5.1. </span>The
    <dt> <strong>normal</strong>
 
    <dd>
-    <p> Corresponds to +0.0dB, which means that there is no modification to
-     the default volume level. This value overrides the inherited value.</p>
+    <p> Corresponds to +0.0dB, which means that there is no modification of
+     volume level. This value overrides the inherited value.</p>
 
    <dt> <strong>silent</strong>
 
@@ -614,10 +614,10 @@ <h3 id=mixing-props-voice-volume><span class=secno>5.1. </span>The
    <dd>
     <p>A <a href="#number-def">number</a> immediately followed by "dB"
      (decibel unit). This represents a change (positive or negative) relative
-     to the default or inherited volume level. This is expressed as the ratio
-     of the squares of the new signal amplitude (a1) and the current
-     amplitude (a0), as per the following logarithmic equation: volume(dB) =
-     20 log10 (a1 / a0)</p>
+     to the default value for the root element, or to the inherited volume
+     level otherwise. This is expressed as the ratio of the squares of the
+     new signal amplitude (a1) and the current amplitude (a0), as per the
+     following logarithmic equation: volume(dB) = 20 log10 (a1 / a0)</p>
 
     <p class=note> Note that -6.0dB is approximately half the amplitude of
      the audio signal, and +6.0dB is approximately twice the amplitude.</p>

css3-speech/Overview.src.html

@@ -306,8 +306,8 @@ <h3 id="mixing-props-voice-volume">The 'voice-volume' property</h3>
         <strong>normal</strong>
       </dt>
       <dd>
-        <p> Corresponds to +0.0dB, which means that there is no modification to the default volume
-          level. This value overrides the inherited value.</p>
+        <p> Corresponds to +0.0dB, which means that there is no modification of volume level. This
+          value overrides the inherited value.</p>
       </dd>
       <dt>
         <strong>silent</strong>
@@ -339,10 +339,10 @@ <h3 id="mixing-props-voice-volume">The 'voice-volume' property</h3>
       </dt>
       <dd>
         <p>A <a href="#number-def">number</a> immediately followed by "dB" (decibel unit). This
-          represents a change (positive or negative) relative to the default or inherited volume
-          level. This is expressed as the ratio of the squares of the new signal amplitude (a1) and
-          the current amplitude (a0), as per the following logarithmic equation: volume(dB) = 20
-          log10 (a1 / a0) </p>
+          represents a change (positive or negative) relative to the default value for the root
+          element, or to the inherited volume level otherwise. This is expressed as the ratio of the
+          squares of the new signal amplitude (a1) and the current amplitude (a0), as per the
+          following logarithmic equation: volume(dB) = 20 log10 (a1 / a0) </p>
         <p class="note"> Note that -6.0dB is approximately half the amplitude of the audio signal,
           and +6.0dB is approximately twice the amplitude.</p>
       </dd>