diff --git a/docs/development/local-stack.md b/docs/development/local-stack.md
index c6018be..684987a 100644
--- a/docs/development/local-stack.md
+++ b/docs/development/local-stack.md
@@ -105,8 +105,10 @@ The API seed is a no-op unless its documented local fixture identity is set.
 
 The Expo window defaults to Metro with
 `EXPO_PUBLIC_API_URL=http://127.0.0.1:3003`. Use `scripts/dev-local.sh ios` or
-`android` to launch the native application against the same API. Physical
-devices require a reachable host URL rather than loopback.
+`android` to launch the native application against the same API. The native
+launcher supplies a UTF-8 locale inside its sanitized environment so CocoaPods
+does not depend on the calling shell's locale. Physical devices require a
+reachable host URL rather than loopback.
 
 `e2e/maestro/login-screen-smoke.yaml` verifies the native build and Auth shell
 without credentials. `e2e/maestro/login-smoke.yaml` is the authenticated
diff --git a/scripts/dev-local.sh b/scripts/dev-local.sh
index 8f7164e..e99a629 100755
--- a/scripts/dev-local.sh
+++ b/scripts/dev-local.sh
@@ -576,7 +576,8 @@ cmd_native() {
   [ -n "$AUTH_ANON_KEY" ] || die "EXPO_PUBLIC_SUPABASE_ANON_KEY is required for the mobile Auth client."
   assert_allowed_auth
   ensure_infra
-  (cd "$ROOT" && env -i PATH="$PATH" HOME="$HOME" TMPDIR="${TMPDIR:-/tmp}" EXPO_PUBLIC_API_URL="$MOBILE_API_URL" \
+  (cd "$ROOT" && env -i PATH="$PATH" HOME="$HOME" TMPDIR="${TMPDIR:-/tmp}" \
+    LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8 EXPO_PUBLIC_API_URL="$MOBILE_API_URL" \
     EXPO_PUBLIC_SUPABASE_URL="$AUTH_URL" EXPO_PUBLIC_SUPABASE_ANON_KEY="$AUTH_ANON_KEY" \
     npm run "$platform" -w @sauci/mobile)
 }