diff --git a/configuration/configure.ac b/configuration/configure.ac
index 1692700..83462a6 100644
--- a/configuration/configure.ac
+++ b/configuration/configure.ac
@@ -128,6 +128,16 @@
 		[AC_MSG_ERROR([could not find GNU cp])])])
 AC_SUBST([GCP], [$ac_cv_path_GCP])
 
+dnl
+dnl PHP
+dnl
+AC_PATH_PROG(PHP, php)
+AS_IF([$PHP_AVAILABLE],
+	[	AC_MSG_CHECKING([for Numbers_Words package (PHP)])
+		AS_IF([(sh -c "$ac_cv_path_PHP -r 'require AS_ESCAPE(["Numbers/Words.php"]);'" 2>&1 /dev/null | grep 'Failed opening required' 2>&1 > /dev/null)],
+			[	AC_MSG_RESULT([no])
+				AC_MSG_ERROR([could not find Numbers_Words package (PHP)])],
+			[	AC_MSG_RESULT([yes])])])
 
 dnl
 dnl LaTeX and friends.