diff --git a/contribute/style-guide.mdx b/contribute/style-guide.mdx
index 7b0714d8..8e05ad0d 100644
--- a/contribute/style-guide.mdx
+++ b/contribute/style-guide.mdx
@@ -122,7 +122,8 @@ Each safety callout should briefly state the risk, scope, rollback/recovery (if
 
 ## Accessibility
 
-* Use plain English; avoid idioms and culture‑specific references.
+* Use plain English; avoid idioms and culture-specific references.
+* Use American English spelling (e.g., color, analyze).
 * Write descriptive headings and link text.
 * Tables should have headers and units (for example, “Latency (ms)”) and keep cells brief.
 * Provide text alternatives for complex figures when possible.