diff --git a/cmd/wasm/main.go b/cmd/wasm/main.go
index a3c0db2..4f2333d 100644
--- a/cmd/wasm/main.go
+++ b/cmd/wasm/main.go
@@ -21,7 +21,7 @@ func renderToString(_ js.Value, args []js.Value) any {
 	ctx := html.NewContext()
 
 	if len(args) >= 2 {
-		ctx.Locale = args[1].String()
+		ctx.SetLocale(args[1].String())
 	}
 
 	layout := html.NewLayout(variant)
diff --git a/context.go b/context.go
index a2eef2f..3fb7828 100644
--- a/context.go
+++ b/context.go
@@ -1,6 +1,9 @@
 package html
 
-import i18n "dappco.re/go/core/i18n"
+// Translator provides Text() lookups for a rendering context.
+type Translator interface {
+	T(key string, args ...any) string
+}
 
 // Context carries rendering state through the node tree.
 type Context struct {
@@ -8,7 +11,24 @@ type Context struct {
 	Locale       string
 	Entitlements func(feature string) bool
 	Data         map[string]any
-	service      *i18n.Service
+	service      Translator
+}
+
+func applyLocaleToService(svc Translator, locale string) {
+	if svc == nil || locale == "" {
+		return
+	}
+
+	if setter, ok := svc.(interface{ SetLanguage(string) error }); ok {
+		base := locale
+		for i := 0; i < len(base); i++ {
+			if base[i] == '-' || base[i] == '_' {
+				base = base[:i]
+				break
+			}
+		}
+		_ = setter.SetLanguage(base)
+	}
 }
 
 // NewContext creates a new rendering context with sensible defaults.
@@ -18,20 +38,37 @@ func NewContext(locale ...string) *Context {
 		Data: make(map[string]any),
 	}
 	if len(locale) > 0 {
-		ctx.Locale = locale[0]
+		ctx.SetLocale(locale[0])
 	}
 	return ctx
 }
 
-// NewContextWithService creates a rendering context backed by a specific i18n service.
+// NewContextWithService creates a rendering context backed by a specific translator.
 // An optional locale may be provided as the second argument.
-func NewContextWithService(svc *i18n.Service, locale ...string) *Context {
-	ctx := &Context{
-		Data:    make(map[string]any),
-		service: svc,
-	}
-	if len(locale) > 0 {
-		ctx.Locale = locale[0]
-	}
+func NewContextWithService(svc Translator, locale ...string) *Context {
+	ctx := NewContext(locale...)
+	ctx.SetService(svc)
+	return ctx
+}
+
+// SetService swaps the translator used by the context.
+func (ctx *Context) SetService(svc Translator) *Context {
+	if ctx == nil {
+		return nil
+	}
+
+	ctx.service = svc
+	applyLocaleToService(svc, ctx.Locale)
+	return ctx
+}
+
+// SetLocale updates the context locale and reapplies it to the active translator.
+func (ctx *Context) SetLocale(locale string) *Context {
+	if ctx == nil {
+		return nil
+	}
+
+	ctx.Locale = locale
+	applyLocaleToService(ctx.service, ctx.Locale)
 	return ctx
 }
diff --git a/context_test.go b/context_test.go
new file mode 100644
index 0000000..272fe85
--- /dev/null
+++ b/context_test.go
@@ -0,0 +1,72 @@
+// SPDX-Licence-Identifier: EUPL-1.2
+
+package html
+
+import "testing"
+
+type localeTranslator struct {
+	language string
+}
+
+func (t *localeTranslator) T(key string, args ...any) string {
+	if key == "prompt.yes" && t.language == "fr" {
+		return "o"
+	}
+	if key == "prompt.yes" && t.language == "en" {
+		return "y"
+	}
+	return key
+}
+
+func (t *localeTranslator) SetLanguage(language string) error {
+	t.language = language
+	return nil
+}
+
+func TestContext_SetService_AppliesLocale(t *testing.T) {
+	svc := &localeTranslator{}
+	ctx := NewContext("fr-FR")
+
+	if got := ctx.SetService(svc); got != ctx {
+		t.Fatal("SetService should return the same context for chaining")
+	}
+
+	if svc.language != "fr" {
+		t.Fatalf("SetService should apply locale to translator, got %q", svc.language)
+	}
+
+	if got := Text("prompt.yes").Render(ctx); got != "o" {
+		t.Fatalf("SetService locale translation = %q, want %q", got, "o")
+	}
+}
+
+func TestContext_SetLocale_AppliesLocale(t *testing.T) {
+	svc := &localeTranslator{}
+	ctx := NewContextWithService(svc)
+
+	if got := ctx.SetLocale("en-GB"); got != ctx {
+		t.Fatal("SetLocale should return the same context for chaining")
+	}
+
+	if svc.language != "en" {
+		t.Fatalf("SetLocale should apply locale to translator, got %q", svc.language)
+	}
+
+	if got := Text("prompt.yes").Render(ctx); got != "y" {
+		t.Fatalf("SetLocale translation = %q, want %q", got, "y")
+	}
+}
+
+func TestContext_SetService_NilContext(t *testing.T) {
+	var ctx *Context
+	if got := ctx.SetService(nil); got != nil {
+		t.Fatal("SetService on nil context should return nil")
+	}
+}
+
+func TestContext_SetLocale_NilContext(t *testing.T) {
+	var ctx *Context
+	if got := ctx.SetLocale("en-GB"); got != nil {
+		t.Fatal("SetLocale on nil context should return nil")
+	}
+}