diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index ca42d421f..f62e1a639 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -5226,7 +5226,8 @@ model InsightNarrative {
   userId           String   @map("user_id")
   /// "week" | "month".
   period           String
-  /// Resolved UI locale of the prose ("de" | "en").
+  /// Resolved UI locale of the prose — any shipped UI locale, not just de/en:
+  /// the prose is generated per locale, so the row is keyed by it.
   locale           String
   /// UTC YYYY-MM-DD boundary the narrative was generated for.
   dateKey          String   @map("date_key")
diff --git a/src/lib/ai/coach/facts.ts b/src/lib/ai/coach/facts.ts
index c210823f1..265598d64 100644
--- a/src/lib/ai/coach/facts.ts
+++ b/src/lib/ai/coach/facts.ts
@@ -558,7 +558,10 @@ function deterministicFactText(
   subject: string,
   locale: string | undefined,
 ): string {
-  const de = locale?.toLowerCase().startsWith("de") ?? true;
+  // German only for a German reader; every other locale — and an absent one —
+  // composes ENGLISH. The fact text is model-facing memory, so English is the
+  // fallback body; the previous `?? true` made an unknown locale German.
+  const de = locale?.toLowerCase().startsWith("de") ?? false;
   switch (kind) {
     case "allergy":
       return de