diff --git a/config/allconfig/allconfig_integration_test.go b/config/allconfig/allconfig_integration_test.go
index 6eb969da1..f724e1751 100644
--- a/config/allconfig/allconfig_integration_test.go
+++ b/config/allconfig/allconfig_integration_test.go
@@ -25,11 +25,13 @@ weight = 2
 [[module.mounts]]
 source = 'content/en'
 target = 'content'
-lang = 'en'
+[module.mounts.sites.matrix]
+languages = 'en'
 [[module.mounts]]
 source = 'content/sv'
 target = 'content'
-lang = 'sv'
+[module.mounts.sites.matrix]
+languages = 'sv'
 -- content/en/p1.md --
 ---
 title: "p1"
diff --git a/config/allconfig/load_test.go b/config/allconfig/load_test.go
index 10a88d7b7..9f533befb 100644
--- a/config/allconfig/load_test.go
+++ b/config/allconfig/load_test.go
@@ -19,19 +19,23 @@ defaultContentLanguage = 'en'
 [[module.mounts]]
 source = 'content/en'
 target = 'content/en'
-lang = 'en'
+[module.mounts.sites.matrix]
+languages = 'en'
 [[module.mounts]]
 source = 'content/nn'
 target = 'content/nn'
-lang = 'nn'
+[module.mounts.sites.matrix]
+languages = 'nn'
 [[module.mounts]]
 source = 'content/no'
 target = 'content/no'
-lang = 'no'
+[module.mounts.sites.matrix]
+languages = 'no'
 [[module.mounts]]
 source = 'content/sv'
 target = 'content/sv'
-lang = 'sv'
+[module.mounts.sites.matrix]
+languages = 'sv'
 [[module.mounts]]
 source = 'layouts'
 target = 'layouts'
diff --git a/create/content_test.go b/create/content_test.go
index c8c3c1cdd..14320d3b4 100644
--- a/create/content_test.go
+++ b/create/content_test.go
@@ -74,7 +74,6 @@ func TestNewContentFromFile(t *testing.T) {
 	c := qt.New(t)
 
 	for i, cas := range cases {
-
 		c.Run(cas.name, func(c *qt.C) {
 			c.Parallel()
 
@@ -109,7 +108,6 @@ func TestNewContentFromFile(t *testing.T) {
 				}
 			}
 		})
-
 	}
 }
 
@@ -339,10 +337,10 @@ theme = "mytheme"
 [languages]
 [languages.en]
 weight = 1
-languageName = "English"
+label = "English"
 [languages.nn]
 weight = 2
-languageName = "Nynorsk"
+label = "Nynorsk"
 
 [module]
 [[module.mounts]]
@@ -351,11 +349,13 @@ languageName = "Nynorsk"
 [[module.mounts]]
   source = 'content'
   target = 'content'
-  lang = 'en'
+  [module.mounts.sites.matrix]
+  languages = 'en'
 [[module.mounts]]
   source = 'content_nn'
   target = 'content'
-  lang = 'nn'
+  [module.mounts.sites.matrix]
+  languages = 'nn'
 `
 	if mm == nil {
 		mm = afero.NewMemMapFs()
diff --git a/hugolib/config_test.go b/hugolib/config_test.go
index ae5efaf30..2e048df2e 100644
--- a/hugolib/config_test.go
+++ b/hugolib/config_test.go
@@ -315,11 +315,11 @@ baseName = "o1main"
 
 [languages]
 [languages.en]
-languageName = "English"
+label = "English"
 [languages.en.params]
 pl1 = "p1-en-main"
 [languages.nb]
-languageName = "Norsk"
+label = "Norsk"
 [languages.nb.params]
 pl1 = "p1-nb-main"
 
@@ -368,7 +368,7 @@ baseName = "o2theme"
 
 [languages]
 [languages.en]
-languageName = "English2"
+label = "English2"
 [languages.en.params]
 pl1 = "p1-en-theme"
 pl2 = "p2-en-theme"
@@ -377,7 +377,7 @@ name   = "menu-lang-en-main"
 [[languages.en.menu.theme]]
 name   = "menu-lang-en-theme"
 [languages.nb]
-languageName = "Norsk2"
+label = "Norsk2"
 [languages.nb.params]
 pl1 = "p1-nb-theme"
 pl2 = "p2-nb-theme"
@@ -905,16 +905,16 @@ func TestConfigMergeLanguageDeepEmptyLeftSide(t *testing.T) {
 [params]
 p1 = "p1base"
 [languages.en]
-languageCode = 'en-US'
-languageName = 'English'
+locale = 'en-US'
+label = 'English'
 weight = 1
 [languages.en.markup.goldmark.extensions.typographer]
 leftDoubleQuote = '“'   # default “
 rightDoubleQuote = '”'  # default ”
 
 [languages.de]
-languageCode = 'de-DE'
-languageName = 'Deutsch'
+locale = 'de-DE'
+label = 'Deutsch'
 weight = 2
 [languages.de.params]
 p1 = "p1de"
@@ -1000,23 +1000,6 @@ HTACCESS.
 	b.AssertFileContent("public/.htaccess", "HTACCESS")
 }
 
-func TestConfigLanguageCodeTopLevel(t *testing.T) {
-	t.Parallel()
-
-	files := `
--- hugo.toml --
-languageCode = "en-US"
--- layouts/home.html --
-LanguageCode: {{ .Site.LanguageCode }}|{{ site.Language.LanguageCode }}|
-
-
-`
-	b := Test(t, files, TestOptInfo())
-
-	b.AssertLogContains("deprecated")
-	b.AssertFileContent("public/index.html", "LanguageCode: en-US|en-US|")
-}
-
 // See #11159
 func TestConfigOutputFormatsPerLanguage(t *testing.T) {
 	t.Parallel()
diff --git a/hugolib/hugo_modules_test.go b/hugolib/hugo_modules_test.go
index 4ece8463c..cc05aa1e4 100644
--- a/hugolib/hugo_modules_test.go
+++ b/hugolib/hugo_modules_test.go
@@ -69,18 +69,18 @@ path="d"
 
 [languages.en]
 title = "Title in English"
-languageName = "English"
+label = "English"
 weight = 1
 [languages.nn]
-languageName = "Nynorsk"
+label = "Nynorsk"
 weight = 2
 title = "Tittel på nynorsk"
 [languages.nb]
-languageName = "Bokmål"
+label = "Bokmål"
 weight = 3
 title = "Tittel på bokmål"
 [languages.fr]
-languageName = "French"
+label = "French"
 weight = 4
 title = "French Title"
 
@@ -312,7 +312,7 @@ func TestMountSameSource(t *testing.T) {
 	files := `
 -- hugo.toml --
 baseURL = 'https://example.org/'
-languageCode = 'en-us'
+locale = 'en-us'
 title = 'Hugo GitHub Issue #9426'
 
 disableKinds = ['RSS','sitemap','taxonomy','term']
diff --git a/hugolib/hugo_sites_build_test.go b/hugolib/hugo_sites_build_test.go
index 8ea992aa0..23f21c320 100644
--- a/hugolib/hugo_sites_build_test.go
+++ b/hugolib/hugo_sites_build_test.go
@@ -51,7 +51,7 @@ defaultContentLanguage = "nn"
 
 [languages]
 [languages.nn]
-languageName = "Nynorsk"
+label = "Nynorsk"
 weight = 1
 title = "Tittel på Nynorsk"
 [languages.nn.params]
@@ -59,7 +59,7 @@ p1 = "p1nn"
 
 [languages.en]
 title = "Title in English"
-languageName = "English"
+label = "English"
 weight = 2
 [languages.en.params]
 p1 = "p1en"
diff --git a/hugolib/hugo_sites_multihost_test.go b/hugolib/hugo_sites_multihost_test.go
index a3b3a9ff9..3ecfa7e9d 100644
--- a/hugolib/hugo_sites_multihost_test.go
+++ b/hugolib/hugo_sites_multihost_test.go
@@ -31,13 +31,13 @@ staticDir2 = ["staticen"]
 baseURL = "https://example.com/docs"
 weight = 10
 title = "In English"
-languageName = "English"
+label = "English"
 [languages.fr]
 staticDir2 = ["staticfr"]
 baseURL = "https://example.fr"
 weight = 20
 title = "Le Français"
-languageName = "Français"
+label = "Français"
 -- assets/css/main.css --
 body { color: red; }
 -- content/mysect/mybundle/index.md --
diff --git a/hugolib/hugo_smoke_test.go b/hugolib/hugo_smoke_test.go
index 2704257fe..58f36a592 100644
--- a/hugolib/hugo_smoke_test.go
+++ b/hugolib/hugo_smoke_test.go
@@ -72,11 +72,13 @@ weight = 100
 [[module.mounts]]
 source = 'content/en'
 target = 'content'
-lang = 'en'
+[module.mounts.sites.matrix]
+languages = 'en'
 [[module.mounts]]
 source = 'content/nn'
 target = 'content'
-lang = 'nn'
+[module.mounts.sites.matrix]
+languages = 'nn'
 [[module.mounts]]
 source = 'content/all'
 target = 'content'
@@ -611,11 +613,13 @@ target = "data"
 [[module.mounts]]
 source = "content/en"
 target = "content"
-lang = "en"
+[module.mounts.sites.matrix]
+languages = "en"
 [[module.mounts]]
 source = "content/nn"
 target = "content"
-lang = "nn"
+[module.mounts.sites.matrix]
+languages = "nn"
 [[module.imports]]
 path = "mytheme"
 -- layouts/home.html --
@@ -775,19 +779,23 @@ defaultContentLanguage = 'en'
 [[module.mounts]]
 source = 'content/en'
 target = 'content/en'
-lang = 'en'
+[module.mounts.sites.matrix]
+languages = 'en'
 [[module.mounts]]
 source = 'content/nn'
 target = 'content/nn'
-lang = 'nn'
+[module.mounts.sites.matrix]
+languages = 'nn'
 [[module.mounts]]
 source = 'content/no'
 target = 'content/no'
-lang = 'no'
+[module.mounts.sites.matrix]
+languages = 'no'
 [[module.mounts]]
 source = 'content/sv'
 target = 'content/sv'
-lang = 'sv'
+[module.mounts.sites.matrix]
+languages = 'sv'
 [[module.mounts]]
 source = 'layouts'
 target = 'layouts'
diff --git a/hugolib/language_content_dir_test.go b/hugolib/language_content_dir_test.go
index 888f592f5..475fa95e3 100644
--- a/hugolib/language_content_dir_test.go
+++ b/hugolib/language_content_dir_test.go
@@ -63,7 +63,7 @@ func TestContentMountMerge(t *testing.T) {
 	files := `
 -- hugo.toml --
 baseURL = 'https://example.org/'
-languageCode = 'en-us'
+locale = 'en-us'
 title = 'Hugo Forum Topic #37225'
 theme = 'mytheme'
 
@@ -72,44 +72,49 @@ defaultContentLanguage = 'en'
 defaultContentLanguageInSubdir = true
 
 [languages.en]
-languageName = 'English'
+label = 'English'
 weight = 1
 [languages.de]
-languageName = 'Deutsch'
+label = 'Deutsch'
 weight = 2
 [languages.nl]
-languageName = 'Nederlands'
+label = 'Nederlands'
 weight = 3
 
 # EN content
 [[module.mounts]]
 source = 'content/en'
 target = 'content'
-lang = 'en'
+[module.mounts.sites.matrix]
+languages = 'en'
 
 # DE content
 [[module.mounts]]
 source = 'content/de'
 target = 'content'
-lang = 'de'
+[module.mounts.sites.matrix]
+languages = 'de'
 
 # This fills in the gaps in DE content with EN content
 [[module.mounts]]
 source = 'content/en'
 target = 'content'
-lang = 'de'
+[module.mounts.sites.matrix]
+languages = 'de'
 
 # NL content
 [[module.mounts]]
 source = 'content/nl'
 target = 'content'
-lang = 'nl'
+[module.mounts.sites.matrix]
+languages = 'nl'
 
 # This should fill in the gaps in NL content with EN content
 [[module.mounts]]
 source = 'content/en'
 target = 'content'
-lang = 'nl'
+[module.mounts.sites.matrix]
+languages = 'nl'
 
 -- content/de/_index.md --
 ---
@@ -153,7 +158,8 @@ title: "p3 (nl)"
 [[module.mounts]]
 source = 'content/nlt'
 target = 'content'
-lang = 'nl'
+[module.mounts.sites.matrix]
+languages = 'nl'
 -- themes/mytheme/content/nlt/p3.md --
 ---
 title: "p3 theme (nl)"
@@ -255,19 +261,22 @@ weight = 2
 [[module.mounts]]
 source = "content/en"
 target = "content"
-lang = "en"
+[module.mounts.sites.matrix]
+languages = "en"
 
 [[module.mounts]]
 source = "content/es"
 target = "content"
-lang = "es"
+[module.mounts.sites.matrix]
+languages = "es"
 
 # Populate the missing es content with en content
 
 [[module.mounts]]
 source = "content/en"
 target = "content"
-lang = "es"
+[module.mounts.sites.matrix]
+languages = "es"
 -- layouts/all.html --
 {{ .Title }}
 -- content/en/p1.md --
diff --git a/hugolib/page_test.go b/hugolib/page_test.go
index e32ef7399..49d7c456c 100644
--- a/hugolib/page_test.go
+++ b/hugolib/page_test.go
@@ -881,12 +881,12 @@ defaultContentLanguage = "en"
 [languages]
 	[languages.en]
 	title = "Repro"
-	languageName = "English"
+	label = "English"
 	contentDir = "content/en"
 
 	[languages.zh_CN]
 	title = "Repro"
-	languageName = "简体中文"
+	label = "简体中文"
 	contentDir = "content/zh_CN"
 
 [outputFormats]
diff --git a/hugolib/pagecollections_test.go b/hugolib/pagecollections_test.go
index dc43c986c..83d323d3c 100644
--- a/hugolib/pagecollections_test.go
+++ b/hugolib/pagecollections_test.go
@@ -608,7 +608,7 @@ func TestGetPageMultilingual(t *testing.T) {
 	files := `
 -- hugo.toml --
 baseURL = "http://example.org/"
-languageCode = "en-us"
+locale = "en-us"
 defaultContentLanguage = "ru"
 title = "My New Hugo Project"
 uglyurls = true
diff --git a/hugolib/site_stats_test.go b/hugolib/site_stats_test.go
index 8f5ce6867..f7f9e3006 100644
--- a/hugolib/site_stats_test.go
+++ b/hugolib/site_stats_test.go
@@ -41,12 +41,12 @@ pagerSize = 1
 
 [languages]
 [languages.nn]
-languageName = "Nynorsk"
+label = "Nynorsk"
 weight = 1
 title = "Hugo på norsk"
 
 [languages.en]
-languageName = "English"
+label = "English"
 weight = 2
 title = "Hugo in English"
 -- layouts/single.html --
diff --git a/hugolib/site_test.go b/hugolib/site_test.go
index 9909d5b55..7e71db86f 100644
--- a/hugolib/site_test.go
+++ b/hugolib/site_test.go
@@ -451,7 +451,8 @@ func TestClassCollector(t *testing.T) {
 
 			files := fmt.Sprintf(`
 -- hugo.toml --
-minify = %t
+[minify]
+minifyOutput = %t
 
 [build]
   writeStats = true
diff --git a/hugolib/sitemap_test.go b/hugolib/sitemap_test.go
index c2062caa7..92f3388e6 100644
--- a/hugolib/sitemap_test.go
+++ b/hugolib/sitemap_test.go
@@ -59,10 +59,10 @@ defaultContentLanguage = "en"
 [languages]
 [languages.en]
 weight = 1
-languageName = "English"
+label = "English"
 [languages.nn]
 weight = 2
-languageName = "Nynorsk"
+label = "Nynorsk"
 -- content/sect/doc1.md --
 ---
 title: doc1
@@ -139,7 +139,7 @@ disableKinds = ["term", "taxonomy"]
 [languages]
 [languages.en]
 weight = 1
-languageName = "English"
+label = "English"
 [languages.nn]
 weight = 2
 -- layouts/list.xml --
diff --git a/hugolib/sitesmatrix/sitematrix_integration_test.go b/hugolib/sitesmatrix/sitematrix_integration_test.go
index e76e2b7aa..c40309b6e 100644
--- a/hugolib/sitesmatrix/sitematrix_integration_test.go
+++ b/hugolib/sitesmatrix/sitematrix_integration_test.go
@@ -1570,11 +1570,11 @@ defaultContentRoleInSubDir: true
 defaultContentLanguage: en
 languages:
   en:
-    languageName: English
+    label: English
   bn:
-    languageName: Bengali
+    label: Bengali
   fr:
-    languageName: French
+    label: French
 -- layouts/all.html --
 All.
 
diff --git a/langs/i18n/i18n_integration_test.go b/langs/i18n/i18n_integration_test.go
index af06e7b6e..15912e6a0 100644
--- a/langs/i18n/i18n_integration_test.go
+++ b/langs/i18n/i18n_integration_test.go
@@ -167,14 +167,14 @@ b = 'b translated'
 	b.Assert(err.Error(), qt.Contains, "failed to load translations: reserved keys [description] mixed with unreserved keys [a b]: see the lang.Translate documentation for a list of reserved keys")
 }
 
-func TestI18nUseLanguageCodeWhenBothTranslationFilesArePresent(t *testing.T) {
+func TestI18nUseLocaleWhenBothTranslationFilesArePresent(t *testing.T) {
 	t.Parallel()
 
 	filesTemplate := `
 -- hugo.yaml --
 languages:
   en:
-    languageCode: en-us
+    locale: en-us
 -- i18n/en.yml --
 hello: Greetings from en!
 -- i18n/en-us.yml --
@@ -189,11 +189,11 @@ hello: Greetings from en-us!
 	}
 
 	runTest(filesTemplate)
-	runTest(strings.ReplaceAll(filesTemplate, "languageCode: en-us", "languageCode: En-US"))
+	runTest(strings.ReplaceAll(filesTemplate, "locale: en-us", "locale: En-US"))
 	runTest(strings.ReplaceAll(filesTemplate, "-- i18n/en-us.yml --", "-- i18n/en-US.yml --"))
 }
 
-func TestI18nUseLangWhenLanguageCodeFileIsMissing(t *testing.T) {
+func TestI18nUseLangWhenLocaleFileIsMissing(t *testing.T) {
 	t.Parallel()
 
 	filesTemplate := `
@@ -202,7 +202,7 @@ languages:
   en:
     title: English
   pt:
-    languageCode: pt-br
+    locale: pt-br
 -- i18n/en.yml --
 hello: Greetings from en!
 -- i18n/pt.yml --
diff --git a/resources/page/site_integration_test.go b/resources/page/site_integration_test.go
index 2528f6379..af68e5b40 100644
--- a/resources/page/site_integration_test.go
+++ b/resources/page/site_integration_test.go
@@ -29,13 +29,13 @@ disableKinds = ['page','rss','section','sitemap','taxonomy','term']
 defaultContentLanguage = 'de'
 defaultContentLanguageInSubdir = true
 [languages.en]
-languageName = 'English'
+label = 'English'
 weight = 1
 [languages.de]
-languageName = 'Deutsch'
+label = 'Deutsch'
 weight = 2
 -- layouts/home.html --
-{{ hugo.Sites.Default.Language.LanguageName }}
+{{ hugo.Sites.Default.Language.Label }}
 `
 
 	b := hugolib.Test(t, files)
diff --git a/resources/page/testhelpers_test.go b/resources/page/testhelpers_test.go
index d41fe6ec1..fdaee35c1 100644
--- a/resources/page/testhelpers_test.go
+++ b/resources/page/testhelpers_test.go
@@ -60,7 +60,7 @@ func newTestPageWithFile(filename string) *testPage {
 		"en",
 		"UTC",
 		langs.LanguageConfig{
-			LanguageName: "English",
+			Label: "English",
 		},
 		loggers.NewDefault(),
 	)
diff --git a/resources/resource_transformers/templates/templates_integration_test.go b/resources/resource_transformers/templates/templates_integration_test.go
index 6cad28fa9..b26f18e75 100644
--- a/resources/resource_transformers/templates/templates_integration_test.go
+++ b/resources/resource_transformers/templates/templates_integration_test.go
@@ -31,11 +31,11 @@ defaultContentLanguageInSubdir = true
 [Languages.en]
 weight = 10
 title = "In English"
-languageName = "English"
+label = "English"
 [Languages.fr]
 weight = 20
 title = "Le Français"
-languageName = "Français"
+label = "Français"
 -- i18n/en.toml --
 [hello]
 other = "Hello"
diff --git a/tpl/collections/collections_integration_test.go b/tpl/collections/collections_integration_test.go
index 6cd9639a7..52939f3c3 100644
--- a/tpl/collections/collections_integration_test.go
+++ b/tpl/collections/collections_integration_test.go
@@ -319,10 +319,10 @@ title: P3
 ---
 -- layouts/section.html --
 {{ $page := . }}
-WhereEq: {{ range where site.AllPages "Parent" "eq" $page }}{{ .Title }}|{{ end }}$
-WhereDefault: {{ range where site.AllPages "Parent" $page }}{{ .Title }}|{{ end }}$
-RangeIf: {{ range site.AllPages }}{{ if eq .Parent $page }}{{ .Title }}|{{ end }}{{ end }}$
-WhereNe: {{ range where site.AllPages "Parent" "ne" $page }}{{ .Title }}|{{ end }}$
+WhereEq: {{ range where site.Pages "Parent" "eq" $page }}{{ .Title }}|{{ end }}$
+WhereDefault: {{ range where site.Pages "Parent" $page }}{{ .Title }}|{{ end }}$
+RangeIf: {{ range site.Pages }}{{ if eq .Parent $page }}{{ .Title }}|{{ end }}{{ end }}$
+WhereNe: {{ range where site.Pages "Parent" "ne" $page }}{{ .Title }}|{{ end }}$
 `
 
 	b := hugolib.Test(t, files)