diff --git a/src/roff/troff/env.cpp b/src/roff/troff/env.cpp
index 882ad7dc..6c8198e6 100644
--- a/src/roff/troff/env.cpp
+++ b/src/roff/troff/env.cpp
@@ -1657,8 +1657,15 @@ void no_hyphenate()
 void hyphenate_request()
 {
   int n;
+  static int n_max = (HYPHEN_NOT_LAST_LINE | HYPHEN_NOT_LAST_CHARS
+    | HYPHEN_NOT_FIRST_CHARS | HYPHEN_LAST_CHAR
+    | HYPHEN_FIRST_CHAR);
+
   if (has_arg() && get_integer(&n)) {
-    if (((n & HYPHEN_FIRST_CHAR) && (n & HYPHEN_NOT_FIRST_CHARS))
+    if (n > n_max) {
+      warning(WARN_RANGE, "hyphenation request value '%1' not "
+	"supported (maximum %2); ignored", n, n_max);
+    } else if (((n & HYPHEN_FIRST_CHAR) && (n & HYPHEN_NOT_FIRST_CHARS))
 	|| ((n & HYPHEN_LAST_CHAR) && (n & HYPHEN_NOT_LAST_CHARS)))
       warning(WARN_SYNTAX, "contradicting hyphenation flags, ignored");
     else