diff --git a/.release.conf b/.release.conf
index 6401c12..8b4c7a4 100644
--- a/.release.conf
+++ b/.release.conf
@@ -6,6 +6,7 @@
 # Defaults, set here only where this repo differs:
 #   CHARTS_REPO=$HOME/git/charts   CHARTS_DIR=<image basename>
 #   GITEA_LOGIN=Ryuvia            APPVERSION_PREFIX=
+#   PROSE_LANG=en
 
 # Same as the image basename, so this is only stated to be read rather than derived.
 CHARTS_DIR=terdut-server
@@ -15,3 +16,9 @@ CHARTS_DIR=terdut-server
 # version and appVersion from the tag when it publishes -- but people read it, and until
 # 2026-09-01 it said "latest" while the tree headed for a numbered release.
 APPVERSION_PREFIX=v
+
+# English. The Swedish in riksdata and rd-web follows from their subject matter, not from a
+# house style: terdut-server is an on-call tool whose labels, API and data are English, and
+# nothing about it is coupled to Swedish. Code comments and docs here were always English;
+# from 2026-09-01 the release prose is too.
+PROSE_LANG=en