diff --git a/doc/bird.sgml b/doc/bird.sgml
index 869fec1c..d20687be 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -430,11 +430,11 @@ a comment, whitespace characters are treated as a single space. If there's a
 variable number of options, they are grouped using the <cf/{ }/ brackets. Each
 option is terminated by a <cf/;/. Configuration is case sensitive. There are two
 ways how to name symbols (like protocol names, filter names, constants etc.).
-You can either use a simple string starting with a letter followed by any
-combination of letters and numbers (e.g. <cf/R123/, <cf/myfilter/, <cf/bgp5/) or
-you can enclose the name into apostrophes (<cf/'/) and than you can use any
-combination of numbers, letters. hyphens, dots and colons (e.g.
-<cf/'1:strange-name'/, <cf/'-NAME-'/, <cf/'cool::name'/).
+You can either use a simple string starting with a letter (or underscore)
+followed by any combination of letters, numbers and underscores (e.g. <cf/R123/,
+<cf/my_filter/, <cf/bgp5/) or you can enclose the name into apostrophes (<cf/'/)
+and than you can use any combination of numbers, letters, underscores, hyphens,
+dots and colons (e.g.  <cf/'1:strange-name'/, <cf/'-NAME-'/, <cf/'cool::name'/).
 
 <p>Here is an example of a simple config file. It enables synchronization of
 routing tables with OS kernel, learns network interfaces and runs RIP on all
@@ -570,7 +570,7 @@ include "tablename.conf";;
 
 	<tag><label id="opt-attribute">attribute <m/type/ <m/name/</tag>
 	Declare a custom route attribute. You can set and get it in filters like
-	any other route atribute. This feature is intended for marking routes
+	any other route attribute. This feature is intended for marking routes
 	in import filters for export filtering purposes instead of locally
 	assigned BGP communities which have to be deleted in export filters.
 
@@ -1234,8 +1234,8 @@ bird>
 <label id="data-types">
 
 <p>Each variable and each value has certain type. Booleans, integers and enums
-are incompatible with each other (that is to prevent you from shooting in the
-foot).
+are incompatible with each other (that is to prevent you from shooting oneself
+in the foot).
 
 <descrip>
 	<tag><label id="type-bool">bool</tag>
@@ -1272,7 +1272,7 @@ foot).
 	This type can hold a single IP address. The IPv4 addresses are stored as
 	IPv4-Mapped IPv6 addresses so one data type for both of them is used.
 	Whether the address is IPv4 or not may be checked by <cf>.is_ip4</cf>
-	which returns <cf/bool/. IP addresses are written in the standard
+	which returns a <cf/bool/. IP addresses are written in the standard
 	notation (<cf/10.20.30.40/ or <cf/fec0:3:4::1/). You can apply special
 	operator <cf>.mask(<M>num</M>)</cf> on values of type ip. It masks out
 	all but first <cf><M>num</M></cf> bits from the IP address. So
@@ -1510,7 +1510,7 @@ foot).
 	<cf/!&tilde;/ membership operators) can be used to modify or test
 	eclists, with ECs instead of pairs as arguments.
 
-	<tag><label id="type-lclist">lclist/</tag>
+	<tag><label id="type-lclist">lclist</tag>
 	Lclist is a data type used for BGP large community lists. Like eclists,
 	lclists are very similar to clists, but they are sets of LCs instead of
 	pairs. The same operations (like <cf/add/, <cf/delete/ or <cf/&tilde;/
@@ -1542,8 +1542,8 @@ the clist that is also a member of the pair/quad set).
 <p>There is one operator related to ROA infrastructure - <cf/roa_check()/. It
 examines a ROA table and does <rfc id="6483"> route origin validation for a
 given network prefix. The basic usage is <cf>roa_check(<m/table/)</cf>, which
-checks current route (which should be from BGP to have AS_PATH argument) in the
-specified ROA table and returns ROA_UNKNOWN if there is no relevant ROA,
+checks the current route (which should be from BGP to have AS_PATH argument) in
+the specified ROA table and returns ROA_UNKNOWN if there is no relevant ROA,
 ROA_VALID if there is a matching ROA, or ROA_INVALID if there are some relevant
 ROAs but none of them match. There is also an extended variant
 <cf>roa_check(<m/table/, <m/prefix/, <m/asn/)</cf>, which allows to specify a
@@ -4809,7 +4809,7 @@ protocol rpki {
 filter peer_in_v4 {
 	if (roa_check(r4, net, bgp_path.last) = ROA_INVALID) then
 	{
-		print "Ignore invalid ROA ", net, " for ASN ", bgp_path.last;
+		print "Ignore RPKI invalid ", net, " for ASN ", bgp_path.last;
 		reject;
 	}
 	accept;