diff --git a/modules/translation/i18n/dummy.go b/modules/translation/i18n/dummy.go
new file mode 100644
index 0000000000..fe15c250f4
--- /dev/null
+++ b/modules/translation/i18n/dummy.go
@@ -0,0 +1,66 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package i18n
+
+import (
+	"fmt"
+	"html/template"
+	"reflect"
+	"slices"
+	"strings"
+)
+
+type KeyLocale struct{}
+
+var _ Locale = (*KeyLocale)(nil)
+
+// HasKey implements Locale.
+func (k *KeyLocale) HasKey(trKey string) bool {
+	return true
+}
+
+// TrHTML implements Locale.
+func (k *KeyLocale) TrHTML(trKey string, trArgs ...any) template.HTML {
+	args := slices.Clone(trArgs)
+	for i, v := range args {
+		switch v := v.(type) {
+		case nil, bool, int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64, template.HTML:
+			// for most basic types (including template.HTML which is safe), just do nothing and use it
+		case string:
+			args[i] = template.HTMLEscapeString(v)
+		case fmt.Stringer:
+			args[i] = template.HTMLEscapeString(v.String())
+		default:
+			args[i] = template.HTMLEscapeString(fmt.Sprint(v))
+		}
+	}
+	return template.HTML(k.TrString(trKey, args...))
+}
+
+// TrString implements Locale.
+func (k *KeyLocale) TrString(trKey string, trArgs ...any) string {
+	return FormatDummy(trKey, trArgs...)
+}
+
+func FormatDummy(trKey string, args ...any) string {
+	if len(args) == 0 {
+		return fmt.Sprintf("(%s)", trKey)
+	}
+
+	fmtArgs := make([]any, 0, len(args)+1)
+	fmtArgs = append(fmtArgs, trKey)
+	for _, arg := range args {
+		val := reflect.ValueOf(arg)
+		if val.Kind() == reflect.Slice {
+			for i := 0; i < val.Len(); i++ {
+				fmtArgs = append(fmtArgs, val.Index(i).Interface())
+			}
+		} else {
+			fmtArgs = append(fmtArgs, arg)
+		}
+	}
+
+	template := fmt.Sprintf("(%%s: %s)", strings.Join(slices.Repeat([]string{"%v"}, len(fmtArgs)-1), ", "))
+	return fmt.Sprintf(template, fmtArgs...)
+}
diff --git a/modules/translation/i18n/dummy_test.go b/modules/translation/i18n/dummy_test.go
new file mode 100644
index 0000000000..7bc29ef839
--- /dev/null
+++ b/modules/translation/i18n/dummy_test.go
@@ -0,0 +1,19 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package i18n_test
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/modules/translation/i18n"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFormatDummy(t *testing.T) {
+	assert.Equal(t, "(admin.config.git_max_diff_lines)", i18n.FormatDummy("admin.config.git_max_diff_lines"))
+	assert.Equal(t, "(dashboard)", i18n.FormatDummy("dashboard"))
+	assert.Equal(t, "(branch.create_branch: main)", i18n.FormatDummy("branch.create_branch", "main"))
+	assert.Equal(t, "(test.test: a, 1, true)", i18n.FormatDummy("test.test", "a", 1, true))
+}
diff --git a/modules/translation/translation.go b/modules/translation/translation.go
index 16eb55e28e..6687d3d817 100644
--- a/modules/translation/translation.go
+++ b/modules/translation/translation.go
@@ -160,6 +160,16 @@ func NewLocale(lang string) Locale {
 		defer lock.RUnlock()
 	}
 
+	if lang == "dummy" {
+		l := &locale{
+			Locale:     &i18n.KeyLocale{},
+			Lang:       lang,
+			LangName:   lang,
+			msgPrinter: message.NewPrinter(language.English),
+		}
+		return l
+	}
+
 	langName := "unknown"
 	if l, ok := allLangMap[lang]; ok {
 		langName = l.Name
diff --git a/modules/web/middleware/locale.go b/modules/web/middleware/locale.go
index 34a16f04e7..1f37407201 100644
--- a/modules/web/middleware/locale.go
+++ b/modules/web/middleware/locale.go
@@ -26,8 +26,10 @@ func Locale(resp http.ResponseWriter, req *http.Request) translation.Locale {
 		}
 	}
 
-	// Check again in case someone changes the supported language list.
-	if lang != "" && !i18n.DefaultLocales.HasLang(lang) {
+	if lang == "dummy" {
+		changeLang = false
+	} else if lang != "" && !i18n.DefaultLocales.HasLang(lang) {
+		// Check again in case someone changes the supported language list.
 		lang = ""
 		changeLang = false
 	}
diff --git a/tests/integration/dummy_lang_test.go b/tests/integration/dummy_lang_test.go
new file mode 100644
index 0000000000..d26ea6edc4
--- /dev/null
+++ b/tests/integration/dummy_lang_test.go
@@ -0,0 +1,24 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package integration
+
+import (
+	"net/http"
+	"testing"
+
+	"code.gitea.io/gitea/tests"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestKeyLocale(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	req := NewRequest(t, "GET", "/user2/repo1/issues?lang=dummy")
+	resp := MakeRequest(t, req, http.StatusOK)
+
+	htmlDoc := NewHTMLParser(t, resp.Body)
+	newButton := htmlDoc.doc.Find(".list-header-issues > .issue-list-new")
+	assert.Equal(t, "(repo.issues.new)", newButton.Text())
+}