diff --git a/Cargo.lock b/Cargo.lock
index c97c5927929..9dd4bbe9c7a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1208,7 +1208,7 @@ dependencies = [
 [[package]]
 name = "derive_common"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "darling",
  "proc-macro2",
@@ -3463,7 +3463,7 @@ dependencies = [
 [[package]]
 name = "malloc_size_of"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "accountable-refcell",
  "app_units",
@@ -5075,7 +5075,7 @@ dependencies = [
 [[package]]
 name = "selectors"
 version = "0.24.0"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "bitflags 1.3.2",
  "cssparser",
@@ -5363,7 +5363,7 @@ dependencies = [
 [[package]]
 name = "servo_arc"
 version = "0.2.0"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "nodrop",
  "serde",
@@ -5373,7 +5373,7 @@ dependencies = [
 [[package]]
 name = "servo_atoms"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "string_cache",
  "string_cache_codegen",
@@ -5579,7 +5579,7 @@ checksum = "38b58827f4464d87d377d175e90bf58eb00fd8716ff0a62f80356b5e61555d0d"
 [[package]]
 name = "size_of_test"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "static_assertions",
 ]
@@ -5705,7 +5705,7 @@ checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
 [[package]]
 name = "static_prefs"
 version = "0.1.0"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 
 [[package]]
 name = "str-buf"
@@ -5748,7 +5748,7 @@ dependencies = [
 [[package]]
 name = "style"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "app_units",
  "arrayvec",
@@ -5806,7 +5806,7 @@ dependencies = [
 [[package]]
 name = "style_config"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "lazy_static",
 ]
@@ -5814,7 +5814,7 @@ dependencies = [
 [[package]]
 name = "style_derive"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "darling",
  "derive_common",
@@ -5845,7 +5845,7 @@ dependencies = [
 [[package]]
 name = "style_traits"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "app_units",
  "bitflags 1.3.2",
@@ -6188,7 +6188,7 @@ checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
 [[package]]
 name = "to_shmem"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "cssparser",
  "servo_arc",
@@ -6201,7 +6201,7 @@ dependencies = [
 [[package]]
 name = "to_shmem_derive"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6d01b5972aa3d00acbbe2a9cac98c59934b659e6"
+source = "git+https://github.com/servo/stylo.git?branch=2023-07-23#6614be88ec2b773e397767eb0d0554dd1145e81e"
 dependencies = [
  "darling",
  "derive_common",
diff --git a/components/gfx/font_cache_thread.rs b/components/gfx/font_cache_thread.rs
index 5b954a33346..1ea34f523a7 100644
--- a/components/gfx/font_cache_thread.rs
+++ b/components/gfx/font_cache_thread.rs
@@ -17,8 +17,10 @@ use net_traits::{fetch_async, CoreResourceThread, FetchResponseMsg};
 use serde::{Deserialize, Serialize};
 use servo_atoms::Atom;
 use servo_url::ServoUrl;
-use style::font_face::{EffectiveSources, Source};
-use style::values::computed::font::FamilyName;
+use style::font_face::{FontFaceSourceFormat, FontFaceSourceFormatKeyword, Source};
+use style::media_queries::Device;
+use style::shared_lock::SharedRwLockReadGuard;
+use style::stylesheets::{Stylesheet, StylesheetInDocument};
 use webrender_api::{FontInstanceKey, FontKey};
 
 use crate::font::{FontFamilyDescriptor, FontFamilyName, FontSearchScope};
@@ -130,7 +132,7 @@ pub enum Command {
         IpcSender<Reply>,
     ),
     GetFontInstance(FontKey, Au, IpcSender<FontInstanceKey>),
-    AddWebFont(LowercaseString, EffectiveSources, IpcSender<()>),
+    AddWebFont(LowercaseString, Vec<Source>, IpcSender<()>),
     AddDownloadedWebFont(LowercaseString, ServoUrl, Vec<u8>, IpcSender<()>),
     Exit(IpcSender<()>),
     Ping,
@@ -248,10 +250,10 @@ impl FontCache {
     fn handle_add_web_font(
         &mut self,
         family_name: LowercaseString,
-        mut sources: EffectiveSources,
+        mut sources: Vec<Source>,
         sender: IpcSender<()>,
     ) {
-        let src = if let Some(src) = sources.next() {
+        let src = if let Some(src) = sources.pop() {
             src
         } else {
             sender.send(()).unwrap();
@@ -503,19 +505,58 @@ impl FontCacheThread {
         FontCacheThread { chan }
     }
 
-    pub fn add_web_font(
+    pub fn add_all_web_fonts_from_stylesheet(
         &self,
-        family: FamilyName,
-        sources: EffectiveSources,
-        sender: IpcSender<()>,
-    ) {
-        self.chan
-            .send(Command::AddWebFont(
-                LowercaseString::new(&family.name),
-                sources,
-                sender,
-            ))
-            .unwrap();
+        stylesheet: &Stylesheet,
+        guard: &SharedRwLockReadGuard,
+        device: &Device,
+        font_cache_sender: &IpcSender<()>,
+        synchronous: bool,
+    ) -> usize {
+        let (sender, receiver) = if synchronous {
+            let (sender, receiver) = ipc::channel().unwrap();
+            (Some(sender), Some(receiver))
+        } else {
+            (None, None)
+        };
+
+        let mut number_loading = 0;
+        stylesheet.effective_font_face_rules(&device, guard, |rule| {
+            let font_face = match rule.font_face() {
+                Some(font_face) => font_face,
+                None => return,
+            };
+
+            let sources: Vec<Source> = font_face
+                .sources()
+                .0
+                .iter()
+                .rev()
+                .filter(is_supported_web_font_source)
+                .cloned()
+                .collect();
+            if sources.is_empty() {
+                return;
+            }
+
+            let sender = sender.as_ref().unwrap_or(font_cache_sender).clone();
+            self.chan
+                .send(Command::AddWebFont(
+                    LowercaseString::new(&font_face.family().name),
+                    sources,
+                    sender,
+                ))
+                .unwrap();
+
+            // Either increment the count of loading web fonts, or wait for a synchronous load.
+            if let Some(ref receiver) = receiver {
+                receiver.recv().unwrap();
+            } else {
+                number_loading += 1;
+            }
+        });
+
+        number_loading
     }
 
     pub fn exit(&self) {
@@ -624,3 +665,31 @@ impl fmt::Display for LowercaseString {
         self.inner.fmt(f)
     }
 }
+
+fn is_supported_web_font_source(source: &&Source) -> bool {
+    let url_source = match source {
+        Source::Url(ref url_source) => url_source,
+        Source::Local(_) => return true,
+    };
+    let format_hint = match url_source.format_hint {
+        Some(ref format_hint) => format_hint,
+        None => return true,
+    };
+
+    if matches!(
+        format_hint,
+        FontFaceSourceFormat::Keyword(
+            FontFaceSourceFormatKeyword::Truetype |
+                FontFaceSourceFormatKeyword::Opentype |
+                FontFaceSourceFormatKeyword::Woff
+        )
+    ) {
+        return true;
+    }
+
+    if let FontFaceSourceFormat::String(string) = format_hint {
+        return string == "truetype" || string == "opentype" || string == "woff";
+    }
+
+    false
+}
diff --git a/components/gfx/tests/font_context.rs b/components/gfx/tests/font_context.rs
index 10a193272ec..972fbca2afe 100644
--- a/components/gfx/tests/font_context.rs
+++ b/components/gfx/tests/font_context.rs
@@ -24,6 +24,7 @@ use style::values::computed::font::{
     FamilyName, FontFamily, FontFamilyList, FontFamilyNameSyntax, FontSize, FontStretch, FontStyle,
     FontWeight, SingleFontFamily,
 };
+use style::values::computed::FontLanguageOverride;
 use webrender_api::{FontInstanceKey, FontKey, IdNamespace};
 
 struct TestFontSource {
@@ -100,6 +101,7 @@ fn style() -> FontStyleStruct {
         font_size: FontSize::medium(),
         font_stretch: FontStretch::hundred(),
         hash: 0,
+        font_language_override: FontLanguageOverride::normal(),
     };
     style.compute_font_hash();
     style
diff --git a/components/layout_thread/lib.rs b/components/layout_thread/lib.rs
index 74be9d0cfd9..ebdb06f04ae 100644
--- a/components/layout_thread/lib.rs
+++ b/components/layout_thread/lib.rs
@@ -295,43 +295,6 @@ impl<'a, 'b: 'a> RwData<'a, 'b> {
     }
 }
 
-fn add_font_face_rules(
-    stylesheet: &Stylesheet,
-    guard: &SharedRwLockReadGuard,
-    device: &Device,
-    font_cache_thread: &FontCacheThread,
-    font_cache_sender: &IpcSender<()>,
-    outstanding_web_fonts_counter: &Arc<AtomicUsize>,
-    load_webfonts_synchronously: bool,
-) {
-    if load_webfonts_synchronously {
-        let (sender, receiver) = ipc::channel().unwrap();
-        stylesheet.effective_font_face_rules(&device, guard, |rule| {
-            if let Some(font_face) = rule.font_face() {
-                let effective_sources = font_face.effective_sources();
-                font_cache_thread.add_web_font(
-                    font_face.family().clone(),
-                    effective_sources,
-                    sender.clone(),
-                );
-                receiver.recv().unwrap();
-            }
-        })
-    } else {
-        stylesheet.effective_font_face_rules(&device, guard, |rule| {
-            if let Some(font_face) = rule.font_face() {
-                let effective_sources = font_face.effective_sources();
-                outstanding_web_fonts_counter.fetch_add(1, Ordering::SeqCst);
-                font_cache_thread.add_web_font(
-                    font_face.family().clone(),
-                    effective_sources,
-                    (*font_cache_sender).clone(),
-                );
-            }
-        })
-    }
-}
-
 impl Layout for LayoutThread {
     fn process(&mut self, msg: script_layout_interface::message::Msg) {
         self.handle_request(Request::FromScript(msg));
@@ -644,15 +607,16 @@ impl LayoutThread {
         // Find all font-face rules and notify the font cache of them.
         // GWTODO: Need to handle unloading web fonts.
         if stylesheet.is_effective_for_device(self.stylist.device(), &guard) {
-            add_font_face_rules(
-                &*stylesheet,
-                &guard,
-                self.stylist.device(),
-                &self.font_cache_thread,
-                &self.font_cache_sender,
-                &self.outstanding_web_fonts,
-                self.debug.load_webfonts_synchronously,
-            );
+            let newly_loading_font_count =
+                self.font_cache_thread.add_all_web_fonts_from_stylesheet(
+                    &*stylesheet,
+                    &guard,
+                    self.stylist.device(),
+                    &self.font_cache_sender,
+                    self.debug.load_webfonts_synchronously,
+                );
+            self.outstanding_web_fonts
+                .fetch_add(newly_loading_font_count, Ordering::SeqCst);
         }
     }
 
diff --git a/components/layout_thread_2020/lib.rs b/components/layout_thread_2020/lib.rs
index f3dd538adda..5ab2ca653e3 100644
--- a/components/layout_thread_2020/lib.rs
+++ b/components/layout_thread_2020/lib.rs
@@ -273,42 +273,6 @@ impl<'a, 'b: 'a> RwData<'a, 'b> {
     }
 }
 
-fn add_font_face_rules(
-    stylesheet: &Stylesheet,
-    guard: &SharedRwLockReadGuard,
-    device: &Device,
-    font_cache_thread: &FontCacheThread,
-    font_cache_sender: &IpcSender<()>,
-    outstanding_web_fonts_counter: &Arc<AtomicUsize>,
-    load_webfonts_synchronously: bool,
-) {
-    if load_webfonts_synchronously {
-        let (sender, receiver) = ipc::channel().unwrap();
-        stylesheet.effective_font_face_rules(&device, guard, |rule| {
-            if let Some(font_face) = rule.font_face() {
-                let effective_sources = font_face.effective_sources();
-                font_cache_thread.add_web_font(
-                    font_face.family().clone(),
-                    effective_sources,
-                    sender.clone(),
-                );
-                receiver.recv().unwrap();
-            }
-        })
-    } else {
-        stylesheet.effective_font_face_rules(&device, guard, |rule| {
-            if let Some(font_face) = rule.font_face() {
-                let effective_sources = font_face.effective_sources();
-                outstanding_web_fonts_counter.fetch_add(1, Ordering::SeqCst);
-                font_cache_thread.add_web_font(
-                    font_face.family().clone(),
-                    effective_sources,
-                    (*font_cache_sender).clone(),
-                );
-            }
-        })
-    }
-}
 impl Layout for LayoutThread {
     fn process(&mut self, msg: script_layout_interface::message::Msg) {
         self.handle_request(Request::FromScript(msg));
@@ -578,15 +542,16 @@ impl LayoutThread {
         // Find all font-face rules and notify the font cache of them.
         // GWTODO: Need to handle unloading web fonts.
         if stylesheet.is_effective_for_device(self.stylist.device(), &guard) {
-            add_font_face_rules(
-                &*stylesheet,
-                &guard,
-                self.stylist.device(),
-                &self.font_cache_thread,
-                &self.font_cache_sender,
-                &self.outstanding_web_fonts,
-                self.debug.load_webfonts_synchronously,
-            );
+            let newly_loading_font_count =
+                self.font_cache_thread.add_all_web_fonts_from_stylesheet(
+                    &*stylesheet,
+                    &guard,
+                    self.stylist.device(),
+                    &self.font_cache_sender,
+                    self.debug.load_webfonts_synchronously,
+                );
+            self.outstanding_web_fonts
+                .fetch_add(newly_loading_font_count, Ordering::SeqCst);
         }
     }
 
diff --git a/tests/wpt/meta-legacy-layout/css/css-fonts/font-shorthand-serialization-prevention.html.ini b/tests/wpt/meta-legacy-layout/css/css-fonts/font-shorthand-serialization-prevention.html.ini
index de8c77a330a..4c4eee915bc 100644
--- a/tests/wpt/meta-legacy-layout/css/css-fonts/font-shorthand-serialization-prevention.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-fonts/font-shorthand-serialization-prevention.html.ini
@@ -67,3 +67,39 @@
 
   [Setting font-stretch to normal should not prevent the font shorthand from serializing in computed style]
     expected: FAIL
+
+  [Setting font-language-override to initial should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to initial should not prevent the font shorthand from serializing in computed style]
+    expected: FAIL
+
+  [Setting font-language-override to inherit should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to inherit should not prevent the font shorthand from serializing in computed style]
+    expected: FAIL
+
+  [Setting font-language-override to unset should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to unset should not prevent the font shorthand from serializing in computed style]
+    expected: FAIL
+
+  [Setting font-language-override to revert should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to revert should not prevent the font shorthand from serializing in computed style]
+    expected: FAIL
+
+  [Setting font-language-override to revert-layer should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to revert-layer should not prevent the font shorthand from serializing in computed style]
+    expected: FAIL
+
+  [Setting font-language-override to normal should not prevent the font shorthand from serializing in computed style]
+    expected: FAIL
+
+  [Setting font-language-override to "SRB" should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
diff --git a/tests/wpt/meta-legacy-layout/css/css-fonts/font-shorthand-subproperties-reset.html.ini b/tests/wpt/meta-legacy-layout/css/css-fonts/font-shorthand-subproperties-reset.html.ini
index 94c6da92bc6..5f677a7fdd1 100644
--- a/tests/wpt/meta-legacy-layout/css/css-fonts/font-shorthand-subproperties-reset.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-fonts/font-shorthand-subproperties-reset.html.ini
@@ -1,2 +1,3 @@
 [font-shorthand-subproperties-reset.html]
-  expected: TIMEOUT
+  [Property font-language-override should be reset to its initial value.]
+    expected: FAIL
diff --git a/tests/wpt/meta-legacy-layout/css/css-fonts/inheritance.html.ini b/tests/wpt/meta-legacy-layout/css/css-fonts/inheritance.html.ini
index 9e4c85353fa..21fa79019b9 100644
--- a/tests/wpt/meta-legacy-layout/css/css-fonts/inheritance.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-fonts/inheritance.html.ini
@@ -62,9 +62,6 @@
   [Property font-variant-alternates has initial value normal]
     expected: FAIL
 
-  [Property font-language-override inherits]
-    expected: FAIL
-
   [Property font-optical-sizing has initial value auto]
     expected: FAIL
 
@@ -74,9 +71,6 @@
   [Property font-variant-alternates inherits]
     expected: FAIL
 
-  [Property font-language-override has initial value normal]
-    expected: FAIL
-
   [Property font-synthesis has initial value weight style small-caps]
     expected: FAIL
 
diff --git a/tests/wpt/meta-legacy-layout/css/css-fonts/parsing/font-language-override-computed.html.ini b/tests/wpt/meta-legacy-layout/css/css-fonts/parsing/font-language-override-computed.html.ini
index a5edebe0490..62bcceb8d3b 100644
--- a/tests/wpt/meta-legacy-layout/css/css-fonts/parsing/font-language-override-computed.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-fonts/parsing/font-language-override-computed.html.ini
@@ -5,20 +5,5 @@
   [Property font-language-override value 'normal' computes to 'normal']
     expected: FAIL
 
-  [Property font-language-override value 'normal']
-    expected: FAIL
-
   [Property font-language-override value '"ksw"']
     expected: FAIL
-
-  [Property font-language-override value '"KSW"']
-    expected: FAIL
-
-  [Property font-language-override value '"ENG "']
-    expected: FAIL
-
-  [Property font-language-override value '"en  "']
-    expected: FAIL
-
-  [Property font-language-override value '" en "']
-    expected: FAIL
diff --git a/tests/wpt/meta-legacy-layout/css/css-fonts/parsing/font-language-override-valid.html.ini b/tests/wpt/meta-legacy-layout/css/css-fonts/parsing/font-language-override-valid.html.ini
deleted file mode 100644
index 13692267ac0..00000000000
--- a/tests/wpt/meta-legacy-layout/css/css-fonts/parsing/font-language-override-valid.html.ini
+++ /dev/null
@@ -1,27 +0,0 @@
-[font-language-override-valid.html]
-  [e.style['font-language-override'\] = "\\"ksw\\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "normal" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"KSW\\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"APPH\\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"ENG \\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"tr\\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"en  \\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\" en \\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"1 %\\"" should set the property value]
-    expected: FAIL
diff --git a/tests/wpt/meta/css/css-fonts/font-shorthand-serialization-prevention.html.ini b/tests/wpt/meta/css/css-fonts/font-shorthand-serialization-prevention.html.ini
index 207963186f5..7912a8d6bee 100644
--- a/tests/wpt/meta/css/css-fonts/font-shorthand-serialization-prevention.html.ini
+++ b/tests/wpt/meta/css/css-fonts/font-shorthand-serialization-prevention.html.ini
@@ -16,3 +16,24 @@
 
   [Setting font-variant to none should prevent the font shorthand from serializing in computed style]
     expected: FAIL
+
+  [Setting font-language-override to initial should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to inherit should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to unset should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to revert should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to revert-layer should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to "SRB" should prevent the font shorthand from serializing in specified style]
+    expected: FAIL
+
+  [Setting font-language-override to "SRB" should prevent the font shorthand from serializing in computed style]
+    expected: FAIL
diff --git a/tests/wpt/meta/css/css-fonts/font-shorthand-subproperties-reset.html.ini b/tests/wpt/meta/css/css-fonts/font-shorthand-subproperties-reset.html.ini
index 94c6da92bc6..5f677a7fdd1 100644
--- a/tests/wpt/meta/css/css-fonts/font-shorthand-subproperties-reset.html.ini
+++ b/tests/wpt/meta/css/css-fonts/font-shorthand-subproperties-reset.html.ini
@@ -1,2 +1,3 @@
 [font-shorthand-subproperties-reset.html]
-  expected: TIMEOUT
+  [Property font-language-override should be reset to its initial value.]
+    expected: FAIL
diff --git a/tests/wpt/meta/css/css-fonts/inheritance.html.ini b/tests/wpt/meta/css/css-fonts/inheritance.html.ini
index 1580e850c13..2af1d7adf7a 100644
--- a/tests/wpt/meta/css/css-fonts/inheritance.html.ini
+++ b/tests/wpt/meta/css/css-fonts/inheritance.html.ini
@@ -11,12 +11,6 @@
   [Property font-kerning inherits]
     expected: FAIL
 
-  [Property font-language-override has initial value normal]
-    expected: FAIL
-
-  [Property font-language-override inherits]
-    expected: FAIL
-
   [Property font-optical-sizing has initial value auto]
     expected: FAIL
 
diff --git a/tests/wpt/meta/css/css-fonts/parsing/font-language-override-computed.html.ini b/tests/wpt/meta/css/css-fonts/parsing/font-language-override-computed.html.ini
deleted file mode 100644
index f74df11360a..00000000000
--- a/tests/wpt/meta/css/css-fonts/parsing/font-language-override-computed.html.ini
+++ /dev/null
@@ -1,15 +0,0 @@
-[font-language-override-computed.html]
-  [Property font-language-override value 'normal']
-    expected: FAIL
-
-  [Property font-language-override value '"KSW"']
-    expected: FAIL
-
-  [Property font-language-override value '"ENG "']
-    expected: FAIL
-
-  [Property font-language-override value '"en  "']
-    expected: FAIL
-
-  [Property font-language-override value '" en "']
-    expected: FAIL
diff --git a/tests/wpt/meta/css/css-fonts/parsing/font-language-override-valid.html.ini b/tests/wpt/meta/css/css-fonts/parsing/font-language-override-valid.html.ini
deleted file mode 100644
index 64cd8823472..00000000000
--- a/tests/wpt/meta/css/css-fonts/parsing/font-language-override-valid.html.ini
+++ /dev/null
@@ -1,27 +0,0 @@
-[font-language-override-valid.html]
-  [e.style['font-language-override'\] = "normal" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"KSW\\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"APPH\\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"ENG \\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"ksw\\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"tr\\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"en  \\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\" en \\"" should set the property value]
-    expected: FAIL
-
-  [e.style['font-language-override'\] = "\\"1 %\\"" should set the property value]
-    expected: FAIL