diff --git a/native/watchos/src/BloomWatchApp.swift b/native/watchos/src/BloomWatchApp.swift
index 8d29239..5542aeb 100644
--- a/native/watchos/src/BloomWatchApp.swift
+++ b/native/watchos/src/BloomWatchApp.swift
@@ -22,6 +22,7 @@ import ImageIO
 @_silgen_name("bloom_watchos_touch") func bloom_watchos_touch(_ idx: Int64, _ x: Double, _ y: Double, _ active: Int64)
 @_silgen_name("bloom_watchos_set_screen") func bloom_watchos_set_screen(_ w: Double, _ h: Double)
 @_silgen_name("bloom_watchos_set_bundle_path") func bloom_watchos_set_bundle_path(_ path: UnsafePointer<CChar>)
+@_silgen_name("bloom_watchos_set_language") func bloom_watchos_set_language(_ code: Double)
 
 // Outbound (Rust → Swift) — draw list snapshot
 @_silgen_name("bloom_watchos_frame_count") func bloom_watchos_frame_count() -> UInt64
@@ -238,6 +239,15 @@ struct BloomWatchApp: App {
         if let res = Bundle.main.resourcePath {
             res.withCString { bloom_watchos_set_bundle_path($0) }
         }
+        // Report the user's preferred language before the game thread starts:
+        // packed 2-letter primary subtag (c0*256 + c1, lowercased; script
+        // subtags dropped, zh-Hans -> "zh") per the bloom_get_language contract.
+        let lang = Locale.preferredLanguages.first ?? "en"
+        let primary = lang.split(separator: "-").first.map(String.init) ?? "en"
+        let scalars = Array(primary.lowercased().unicodeScalars)
+        if scalars.count >= 2, scalars[0].isASCII, scalars[1].isASCII {
+            bloom_watchos_set_language(Double(scalars[0].value * 256 + scalars[1].value))
+        }
         // Spawn the game thread. _perry_user_main blocks in runGame's while
         // loop, so this must not run on the main thread.
         let t = Thread(block: { _perry_user_main() })
diff --git a/native/watchos/src/lib.rs b/native/watchos/src/lib.rs
index 04d2993..3f65b04 100644
--- a/native/watchos/src/lib.rs
+++ b/native/watchos/src/lib.rs
@@ -102,6 +102,7 @@ const MAX_TOUCH: usize = 4;
 
 struct WatchState {
     crown_bits: AtomicU64, // f64 bits
+    language_code: AtomicU64, // packed 2-letter code (c0*256+c1), set by Swift at launch
     touch_x: [AtomicU64; MAX_TOUCH],
     touch_y: [AtomicU64; MAX_TOUCH],
     touch_active: [AtomicU64; MAX_TOUCH],
@@ -117,6 +118,7 @@ fn state() -> &'static WatchState {
     static S: OnceLock<WatchState> = OnceLock::new();
     S.get_or_init(|| WatchState {
         crown_bits: AtomicU64::new(0),
+        language_code: AtomicU64::new(25966), // "en" until Swift reports the locale
         touch_x: std::array::from_fn(|_| AtomicU64::new(0)),
         touch_y: std::array::from_fn(|_| AtomicU64::new(0)),
         touch_active: std::array::from_fn(|_| AtomicU64::new(0)),
@@ -162,6 +164,17 @@ fn consume_crown() -> f64 {
 #[no_mangle]
 pub extern "C" fn bloom_watchos_crown_delta(delta: f64) { add_crown(delta); }
 
+/// Swift reports the user's preferred language at launch as a packed
+/// 2-letter ISO-639 primary subtag (c0*256 + c1, lowercased), matching
+/// the bloom_get_language contract on the other platforms.
+#[no_mangle]
+pub extern "C" fn bloom_watchos_set_language(code: f64) {
+    let c = code as u64;
+    if c > 0 {
+        state().language_code.store(c, Ordering::Release);
+    }
+}
+
 #[no_mangle]
 pub extern "C" fn bloom_watchos_touch(index: i64, x: f64, y: f64, active: i64) {
     let s = state();
@@ -252,7 +265,9 @@ pub extern "C" fn bloom_get_platform() -> f64 { 8.0 }
 
 /// Preferred OS language packed as `c0*256+c1`. TODO: real per-OS detection; returns "en" for now.
 #[no_mangle]
-pub extern "C" fn bloom_get_language() -> f64 { 25966.0 }
+pub extern "C" fn bloom_get_language() -> f64 {
+    state().language_code.load(Ordering::Acquire) as f64
+}
 
 #[no_mangle]
 pub extern "C" fn bloom_get_crown_rotation() -> f64 { consume_crown() }