diff --git a/source b/source
index 309eea911f7..c3641e4a082 100644
--- a/source
+++ b/source
@@ -3956,6 +3956,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
     <p>The following features are defined in <cite>CSS Text</cite>: <ref>CSSTEXT</ref></p>
 
     <ul class="brief">
+      <li>The <dfn data-x-href="https://drafts.csswg.org/css-text-4/#content-language">content language</dfn> concept</li>
       <li>The <dfn data-x-href="https://drafts.csswg.org/css-text/#text-transform-property">'text-transform'</dfn> property</li>
       <li>The <dfn data-x-href="https://drafts.csswg.org/css-text/#white-space-property">'white-space'</dfn> property</li>
       <li>The <dfn data-x-href="https://drafts.csswg.org/css-text/#text-align-property">'text-align'</dfn> property</li>
@@ -13608,7 +13609,7 @@ Transport Protocol">HTTP&lt;/abbr> today.&lt;/p></code></pre> <!-- DO NOT REWRAP
   Belarusian).</p>
 
   <p>If the resulting value is the empty string, then it must be interpreted as meaning that the
-  language of the node is explicitly unknown.</p>
+  language of the node is <dfn data-x="concept-explicitly-unknown">explicitly unknown</dfn>.</p>
 
   <hr>
 
@@ -65680,13 +65681,21 @@ callback <dfn callback>BlobCallback</dfn> = undefined (<span>Blob</span>? blob);
    and <code data-x="attr-canvas-height">height</code> content attributes of this
    <code>canvas</code> element.</p></li>
 
-   <li><p>Set the <span data-x="offscreencanvas-placeholder">placeholder <code>canvas</code>
-   element</span> of <var>offscreenCanvas</var> to a weak reference to this <code>canvas</code>
-   element.</p></li>
+   <li><p>Set the <var>offscreenCanvas</var>'s <span
+   data-x="offscreencanvas-placeholder">placeholder <code>canvas</code> element</span>
+   to a weak reference to this <code>canvas</code> element.</p></li>
 
    <li><p>Set this <code>canvas</code> element's <span data-x="concept-canvas-context-mode">context
    mode</span> to <span data-x="concept-canvas-placeholder">placeholder</span>.</p></li>
 
+   <li><p>Set the <var>offscreenCanvas</var>'s <span
+   data-x="offscreencanvas-inherited-lang">inherited language</span> to the
+   <span>language</span> of this <code>canvas</code> element.</p></li>
+
+   <li><p>Set the <var>offscreenCanvas</var>'s <span
+   data-x="offscreencanvas-inherited-direction">inherited direction</span> to the <span
+   data-x="the directionality">directionality</span> of this <code>canvas</code> element.</p></li>
+
    <li><p>Return <var>offscreenCanvas</var>.</p></li>
   </ol>
 
@@ -65900,6 +65909,7 @@ interface mixin <dfn interface>CanvasPathDrawingStyles</dfn> {
 
 interface mixin <dfn interface>CanvasTextDrawingStyles</dfn> {
   // text
+  attribute DOMString <span data-x="dom-context-2d-lang">lang</span>; // (default: "inherit")
   attribute DOMString <span data-x="dom-context-2d-font">font</span>; // (default 10px sans-serif)
   attribute <span>CanvasTextAlign</span> <span data-x="dom-context-2d-textAlign">textAlign</span>; // (default: "start")
   attribute <span>CanvasTextBaseline</span> <span data-x="dom-context-2d-textBaseline">textBaseline</span>; // (default: "alphabetic")
@@ -66406,6 +66416,7 @@ context.fillRect(100,0,50,50); // only this square remains</code></pre>
    data-x="dom-context-2d-shadowOffsetX">shadowOffsetX</code>, <code
    data-x="dom-context-2d-shadowOffsetY">shadowOffsetY</code>, <code
    data-x="dom-context-2d-shadowBlur">shadowBlur</code>, <code
+   data-x="dom-context-2d-lang">lang</code>, <code
    data-x="dom-context-2d-font">font</code>, <code
    data-x="dom-context-2d-textAlign">textAlign</code>, <code
    data-x="dom-context-2d-textBaseline">textBaseline</code>, <code
@@ -66897,13 +66908,28 @@ transform. ack Shaun Morris. -->
   <h6>Text styles</h6>
 
   <dl class="domintro">
+   <dt><code data-x=""><var>context</var>.<span subdfn data-x="dom-context-2d-lang">lang</span> [ = <var>value</var> ]</code></dt>
+   <dt><code data-x=""><var>styles</var>.<span data-x="dom-context-2d-lang">lang</span> [ = <var>value</var> ]</code></dt>
+   <dd>
+    <p>Returns the current language setting.</p>
+
+    <p>Can be set to a BCP 47 language tag, the empty string, or "<code
+    data-x="dom-context-2d-lang-inherit">inherit</code>", to change the language used when
+    resolving fonts. "<code data-x="dom-context-2d-lang-inherit">inherit</code>" takes the language
+    from the <code>canvas</code> element's language, or the associated <span>document
+    element</span> when there is no <code>canvas</code> element.</p>
+
+    <p>The default is "<code data-x="dom-context-2d-lang-inherit">inherit</code>".</p>
+   </dd>
+
    <dt><code data-x=""><var>context</var>.<span subdfn data-x="dom-context-2d-font">font</span> [ = <var>value</var> ]</code></dt>
    <dt><code data-x=""><var>styles</var>.<span data-x="dom-context-2d-font">font</span> [ = <var>value</var> ]</code></dt>
    <dd>
     <p>Returns the current font settings.</p>
 
     <p>Can be set, to change the font. The syntax is the same as for the CSS <span>'font'</span>
-    property; values that cannot be parsed as CSS font values are ignored.</p>
+    property; values that cannot be parsed as CSS font values are ignored. The default is "10px
+    sans-serif".</p>
 
     <p>Relative keywords and lengths are computed relative to the font of the <code>canvas</code>
     element.</p>
@@ -67140,6 +67166,22 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>
   data-x="dom-context-2d-textBaseline">textBaseline</code> attribute must initially have the value
   <code data-x="dom-context-2d-textBaseline-alphabetic">alphabetic</code>.</p>
 
+  <p>Objects that implement the <code>CanvasTextDrawingStyles</code> interface have an associated
+  <dfn data-x="concept-CanvasTextDrawingStyles-language">language</dfn> value used to localize font
+  rendering. Valid values are a BCP 47 language tag, the empty string, or "<dfn
+  data-x="dom-context-2d-lang-inherit">inherit</dfn>" where the language comes from the
+  <code>canvas</code> element's language, or the associated <span>document element</span> when there
+  is no <code>canvas</code> element. Initially, the <span
+  data-x="concept-CanvasTextDrawingStyles-language">language</span> must be "<code
+  data-x="dom-context-2d-lang-inherit">inherit</code>".</p>
+
+  <p>The <dfn attribute for="CanvasTextDrawingStyles" data-x="dom-context-2d-lang"><code
+  data-x="dom-context-2d-lang">lang</code></dfn> getter steps are to return
+  <span>this</span>'s <span data-x="concept-CanvasTextDrawingStyles-language">language</span>.</p>
+
+  <p>The <code data-x="dom-context-2d-lang">lang</code> setter steps are to set <span>this</span>'s
+  <span data-x="concept-CanvasTextDrawingStyles-language">language</span> to the given value.</p>
+
   <p>The <dfn attribute for="CanvasTextDrawingStyles"><code
   data-x="dom-context-2d-direction">direction</code></dfn> IDL attribute, on getting, must return
   the current value. On setting, the current value must be changed to the new value. When the object
@@ -67281,16 +67323,12 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>
 
    <dd><p>Treat input to the <span>text preparation algorithm</span> as right-to-left text.</p></dd>
 
-<!--
-   <dt><dfn><code data-x="dom-context-2d-direction-auto">auto</code></dfn>
-
-   <dd><p>Determine the direction from the input to the <span>text preparation algorithm</span>.</p></dd>
--->
-
    <dt><dfn enum-value for="CanvasDirection"><code data-x="dom-context-2d-direction-inherit">inherit</code></dfn>
 
-   <dd><p>Default to the directionality of the <code>canvas</code> element or <code>Document</code>
-   as appropriate.</p></dd>
+   <dd><p>Use the process in the <span>text preparation algorithm</span> to obtain the text
+   direction from the <code>canvas</code> element, <span
+   data-x="offscreencanvas-placeholder">placeholder <code>canvas</code> element</span>, or
+   <span>document element</span>.</p></dd>
   </dl>
 
   <p>The <code data-x="dom-context-2d-fontKerning">fontKerning</code> attribute's allowed keywords
@@ -67399,8 +67437,39 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>
    <li><p>Let <var>font</var> be the current font of <var>target</var>, as given
    by that object's <code data-x="dom-context-2d-font">font</code> attribute.</p></li>
 
+   <li><p>Let <var>language</var> be the <var>target</var>'s <span
+   data-x="concept-CanvasTextDrawingStyles-language">language</span>.</p></li>
+
+   <li>
+    <p>If <var>language</var> is "<code data-x="dom-context-2d-lang-inherit">inherit</code>":</p>
+
+    <ol>
+     <li><p>Let <var>sourceObject</var> be <var>object</var>'s <span>font style source
+     object</span></p></li>
+
+     <li><p>If <var>sourceObject</var> is a <code>canvas</code>
+     element, then set <var>language</var> to the <var>sourceObject</var>'s
+     <span data-x="language">language</span>.</p></li>
+
+     <li>
+      <p>Otherwise:</p>
+
+      <ol>
+       <li><p>Assert: <var>sourceObject</var> is an <code>OffscreenCanvas</code> object.</p></li>
+
+       <li><p>Set <var>language</var> to the <var>sourceObject</var>'s
+       <span data-x="offscreencanvas-inherited-lang">inherited language</span>.</p></li>
+      </ol>
+     </li>
+    </ol>
+   </li>
+
+   <li><p>If <var>language</var> is the empty string, then set <var>language</var> to
+   <span data-x="concept-explicitly-unknown">explicitly unknown</span>.</p></li>
+
    <li>
-    <p>Apply the appropriate step from the following list to determine the value of <var>direction</var>:</p>
+    <p>Apply the appropriate step from the following list to determine the value of
+    <var>direction</var>:</p>
 
     <dl class="switch">
 
@@ -67414,38 +67483,36 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>
      data-x="dom-context-2d-direction-rtl">rtl</code>"</dt>
      <dd>Let <var>direction</var> be '<span data-x="concept-rtl">rtl</span>'.</dd>
 
-<!--
      <dt>If the <var>target</var> object's <code
      data-x="dom-context-2d-direction">direction</code> attribute has the value "<code
-     data-x="dom-context-2d-direction-auto">auto</code>"</dt>
+     data-x="dom-context-2d-direction-inherit">inherit</code>"</dt>
      <dd>
-      Find the first character in <var>text</var> of bidirectional character type L, AL, or
-      R, if any. If such a character is found and it is of bidirectional character type AL or R,
-      then let <var>direction</var> be '<span data-x="concept-rtl">rtl</span>'; otherwise,
-      let <var>direction</var> be '<span data-x="concept-rtl">rtl</span>'. <ref>BIDI</ref>
-     </dd>
--->
-
-     <dt>If the <var>target</var> object's <span>font style source object</span> is an
-     element</dt>
-
-     <dd>Let <var>direction</var> be <span>the directionality</span> of the <var>target</var> object's <span>font style source object</span>.</dd>
-
-     <dt>If the <var>target</var> object's <span>font style source object</span> is a
-     <code>Document</code> with a non-null <span>document element</span></dt>
+      <ol>
+       <li><p>Let <var>sourceObject</var> be <var>object</var>'s <span>font style source
+       object</span></p></li>
 
-     <dd>Let <var>direction</var> be <span>the directionality</span> of the <var>target</var>
-     object's <span>font style source object</span>'s <span>document element</span>.</dd>
+       <li><p>If <var>sourceObject</var> is a <code>canvas</code>
+       element, then let <var>direction</var> be <var>sourceObject</var>'s
+       <span data-x="the directionality">directionality</span>.</p></li>
 
-     <dt>Otherwise</dt>
+       <li>
+        <p>Otherwise:</p>
+        <ol>
+         <li><p>Assert: <var>sourceObject</var> is an <code>OffscreenCanvas</code> object.</p></li>
 
-     <dd>Let <var>direction</var> be '<span data-x="concept-ltr">ltr</span>'.</dd>
+         <li><p>Let <var>direction</var> be <var>sourceObject</var>'s
+         <span data-x="offscreencanvas-inherited-direction">inherited direction</span>.</p></li>
+        </ol>
+       </li>
+      </ol>
+     </dd>
     </dl>
    </li>
 
    <li>
     <p>Form a hypothetical infinitely-wide CSS <span>line box</span> containing a single
-    <span>inline box</span> containing the text <var>text</var>, with its CSS properties set as
+    <span>inline box</span> containing the text <var>text</var>, with the CSS
+    <span>content language</span> set to <var>language</var>, and with its CSS properties set as
     follows:</p>
 
     <table>
@@ -71664,6 +71731,11 @@ interface <dfn interface>OffscreenCanvas</dfn> : <span>EventTarget</span> {
   data-x="dom-OffscreenCanvas-height">height</code> attributes of the <code>OffscreenCanvas</code>
   object. Initially, all the bitmap's pixels are <span>transparent black</span>.</p>
 
+  <p>An <code>OffscreenCanvas</code> object has an internal <dfn
+  data-x="offscreencanvas-inherited-lang">inherited language</dfn> and <dfn
+  data-x="offscreencanvas-inherited-direction">inherited direction</dfn> set when
+  the <code>OffscreenCanvas</code> is created.</p>
+
   <p>An <code>OffscreenCanvas</code> object can have a rendering context bound to it. Initially,
   it does not have a bound rendering context. To keep track of whether it has a rendering context
   or not, and what kind of rendering context it is, an <code>OffscreenCanvas</code> object also
@@ -71677,16 +71749,52 @@ interface <dfn interface>OffscreenCanvas</dfn> : <span>EventTarget</span> {
   data-x="offscreencanvas-context-detached">detached</dfn> by algorithms defined in this
   specification.</p>
 
-  <p>The constructor <dfn constructor for="OffscreenCanvas"
-  data-x="dom-OffscreenCanvas"><code>OffscreenCanvas(<var>width</var>,
-  <var>height</var>)</code></dfn>, when invoked, must create a new <code>OffscreenCanvas</code>
-  object with its <span data-x="offscreencanvas-bitmap">bitmap</span> initialized to a rectangular
-  array of <span>transparent black</span> pixels of the dimensions specified by <var>width</var> and
-  <var>height</var>; and its <code data-x="dom-OffscreenCanvas-width">width</code> and <code
-  data-x="dom-OffscreenCanvas-height">height</code> attributes initialized to <var>width</var> and
-  <var>height</var> respectively.</p>
+  <p>The <dfn constructor for="OffscreenCanvas"><code data-x="dom-OffscreenCanvas">new OffscreenCanvas(<var>width</var>,
+  <var>height</var>)</code></dfn> constructor steps are:</p>
 
-  <hr>
+  <ol>
+   <li><p>Initialize the <span data-x="offscreencanvas-bitmap">bitmap</span> of <span>this</span>
+   to a rectangular array of <span>transparent black</span> pixels of the dimensions specified
+   by <var>width</var> and <var>height</var>.</p></li>
+
+   <li><p>Initialize the <code data-x="dom-OffscreenCanvas-width">width</code> of <span>this</span>
+   to <var>width</var>.</p></li>
+
+   <li><p>Initialize the <code data-x="dom-OffscreenCanvas-height">height</code> of
+   <span>this</span> to <var>height</var>.</p></li>
+
+   <li><p>Set <span>this</span>'s <span data-x="offscreencanvas-inherited-lang">inherited
+   language</span> to <span data-x="concept-explicitly-unknown">explicitly unknown</span>.</p></li>
+
+   <li><p>Set <span>this</span>'s <span data-x="offscreencanvas-inherited-direction">inherited
+   direction</span> to "<code data-x="">ltr</code>".</p></li>
+
+   <li><p>Let <var>global</var> be the <span>relevant global object</span> of
+   <span>this</span>.</p></li>
+
+   <li>
+    <p>If <var>global</var> is a <code>Window</code> object:</p>
+
+    <ol>
+     <li><p>Let <var>element</var> be the <span>document element</span> of <var>global</var>'s
+     <span data-x="concept-document-window">associated <code>Document</code></span>.</p></li>
+
+     <li>
+      <p>If <var>element</var> is not null:</p>
+
+      <ol>
+       <li><p>Set the <span data-x="offscreencanvas-inherited-lang">inherited language</span>
+       of <span>this</span> to <var>element</var>'s <span
+       data-x="language">language</span>.</p></li>
+
+       <li><p>Set the <span data-x="offscreencanvas-inherited-direction">inherited
+       direction</span> of <span>this</span> to <var>element</var>'s <span
+       data-x="the directionality">directionality</span>.</p></li>
+      </ol>
+     </li>
+    </ol>
+   </li>
+  </ol>
 
   <p><code>OffscreenCanvas</code> objects are <span data-x="transferable
   objects">transferable</span>. Their <span>transfer steps</span>, given <var>value</var> and
@@ -71703,11 +71811,18 @@ interface <dfn interface>OffscreenCanvas</dfn> : <span>EventTarget</span> {
    <li><p>Let <var>width</var> and <var>height</var> be the dimensions of <var>value</var>'s <span
    data-x="offscreencanvas-bitmap">bitmap</span>.</p></li>
 
+   <li><p>Let <var>language</var> and <var>direction</var> be the values of <var>value</var>'s
+   <span data-x="offscreencanvas-inherited-lang">inherited language</span> and
+   <span data-x="offscreencanvas-inherited-direction">inherited direction</span>.</p></li>
+
    <li><p>Unset <var>value</var>'s <span data-x="offscreencanvas-bitmap">bitmap</span>.</p></li>
 
    <li><p>Set <var>dataHolder</var>.[[Width]] to <var>width</var> and
    <var>dataHolder</var>.[[Height]] to <var>height</var>.</p></li>
 
+   <li><p>Set <var>dataHolder</var>.[[Language]] to <var>language</var> and
+   <var>dataHolder</var>.[[Direction]] to <var>direction</var>.</p></li>
+
    <li><p>Set <var>dataHolder</var>.[[PlaceholderCanvas]] to be a weak reference to
    <var>value</var>'s <span data-x="offscreencanvas-placeholder">placeholder <code>canvas</code>
    element</span>, if <var>value</var> has one, or null if it does not.</p></li>
@@ -71721,6 +71836,11 @@ interface <dfn interface>OffscreenCanvas</dfn> : <span>EventTarget</span> {
    rectangular array of <span>transparent black</span> pixels with width given by
    <var>dataHolder</var>.[[Width]] and height given by <var>dataHolder</var>.[[Height]].</p></li>
 
+   <li><p>Set <var>value</var>'s <span data-x="offscreencanvas-inherited-lang">inherited
+   language</span> to <var>dataHolder</var>.[[Language]] and <span
+   data-x="offscreencanvas-inherited-direction">inherited direction</span> to
+   <var>dataHolder</var>.[[Direction]].</p></li>
+
    <li><p>If <var>dataHolder</var>.[[PlaceholderCanvas]] is not null, set <var>value</var>'s <span
    data-x="offscreencanvas-placeholder">placeholder <code>canvas</code> element</span> to
    <var>dataHolder</var>.[[PlaceholderCanvas]] (while maintaining the weak reference
@@ -147514,6 +147634,7 @@ INSERT INTERFACES HERE
   Ştefan Vargyas,
   Stefan Weiss,
   Steffen Meschkat,
+  Stephen Chenney,
   Stephen Ma,
   Stephen Stewart,
   Stephen White,