diff --git a/src/lib/client/appointment-crypto.ts b/src/lib/client/appointment-crypto.ts
index 64eec52..94ee141 100644
--- a/src/lib/client/appointment-crypto.ts
+++ b/src/lib/client/appointment-crypto.ts
@@ -74,6 +74,7 @@ export interface AppointmentData {
   email: string;
   shareEmail: boolean;
   phone?: string;
+  locale?: string;
 }
 
 interface StaffPublicKey {
diff --git a/src/lib/types/public.ts b/src/lib/types/public.ts
index 27afd4d..f32c711 100644
--- a/src/lib/types/public.ts
+++ b/src/lib/types/public.ts
@@ -44,6 +44,7 @@ export type TPublicAppointment = {
     shareEmail: boolean;
     email: string;
     phone?: string;
+    locale: string;
   };
   isNewClient?: boolean;
 };
diff --git a/src/routes/(pages)/(clients)/book-appointment/[[id]]/(components)/add-personal-data-form/add-personal-data-form.svelte b/src/routes/(pages)/(clients)/book-appointment/[[id]]/(components)/add-personal-data-form/add-personal-data-form.svelte
index dea9ae0..36f8bf4 100644
--- a/src/routes/(pages)/(clients)/book-appointment/[[id]]/(components)/add-personal-data-form/add-personal-data-form.svelte
+++ b/src/routes/(pages)/(clients)/book-appointment/[[id]]/(components)/add-personal-data-form/add-personal-data-form.svelte
@@ -43,6 +43,7 @@
               shareEmail: validation.data.shareEmail,
               email: validation.data.email,
               phone: validation.data.phone,
+              locale: navigator.language || "en",
             },
           });
           cancel();