diff --git a/debug.go b/debug.go
index de6739c..898acb4 100644
--- a/debug.go
+++ b/debug.go
@@ -1,5 +1,7 @@
 package i18n
 
+import "dappco.re/go/core"
+
 // SetDebug enables or disables debug mode on the default service.
 func SetDebug(enabled bool) {
 	withDefaultService(func(svc *Service) { svc.SetDebug(enabled) })
@@ -18,5 +20,5 @@ func (s *Service) Debug() bool {
 }
 
 func debugFormat(key, text string) string {
-	return "[" + key + "] " + text
+	return core.Sprintf("[%s] %s", key, text)
 }
diff --git a/i18n.go b/i18n.go
index a5e820b..7f83c04 100644
--- a/i18n.go
+++ b/i18n.go
@@ -3,7 +3,6 @@ package i18n
 import (
 	"bytes"
 	"io/fs"
-	"strings"
 	"text/template"
 
 	"dappco.re/go/core"
@@ -308,7 +307,7 @@ func namespaceLookupKey(namespace, key string) string {
 	if namespace != "" && key == namespace {
 		return key
 	}
-	if namespace != "" && strings.HasPrefix(key, namespace+".") {
+	if namespace != "" && core.HasPrefix(key, namespace+".") {
 		return key
 	}
 	if namespace == "" {
diff --git a/state.go b/state.go
index 9c3501c..bb18608 100644
--- a/state.go
+++ b/state.go
@@ -1,8 +1,7 @@
 package i18n
 
 import (
-	"fmt"
-	"strings"
+	"dappco.re/go/core"
 )
 
 // ServiceState captures the current configuration of a service in one
@@ -24,9 +23,9 @@ type ServiceState struct {
 func (s ServiceState) String() string {
 	langs := "[]"
 	if len(s.AvailableLanguages) > 0 {
-		langs = "[" + strings.Join(s.AvailableLanguages, ", ") + "]"
+		langs = "[" + core.Join(", ", s.AvailableLanguages...) + "]"
 	}
-	return fmt.Sprintf(
+	return core.Sprintf(
 		"ServiceState{language=%q fallback=%q mode=%s formality=%s location=%q direction=%s rtl=%t debug=%t available=%s handlers=%d}",
 		s.Language,
 		s.Fallback,