Index: src/XMPPConnection.h
==================================================================
--- src/XMPPConnection.h
+++ src/XMPPConnection.h
@@ -144,10 +144,11 @@
 	OFString *username, *password, *server, *resource;
 	OFString *privateKeyFile, *certificateFile;
 	OFString *domain, *domainToASCII;
 	XMPPJID *JID;
 	uint16_t port;
+	OFString *language;
 	XMPPMulticastDelegate *delegates;
 	OFMutableDictionary *callbacks;
 	XMPPAuthenticator *authModule;
 	BOOL streamOpen;
 	BOOL needsSession;
@@ -168,10 +169,12 @@
 @property (copy) OFString *server;
 /// \brief The domain to connect to
 @property (copy) OFString *domain;
 /// \brief The resource to request for the connection
 @property (copy) OFString *resource;
+/// \brief The language to request for the connection
+@property (copy) OFString *language;
 /// \brief A private key file to use for authentication
 @property (copy) OFString *privateKeyFile;
 /// \brief A certificate file to use for authentication
 @property (copy) OFString *certificateFile;
 /// \brief The JID the server assigned to the connection after binding
@@ -319,10 +322,12 @@
 - (void)setResource: (OFString*)resource;
 - (OFString*)resource;
 - (XMPPJID*)JID;
 - (void)setPort: (uint16_t)port;
 - (uint16_t)port;
+- (void)setLanguage: (OFString*)language;
+- (OFString*)language;
 
 /// \cond internal
 - (void)XMPP_startStream;
 - (void)XMPP_handleStream: (OFXMLElement*)element;
 - (void)XMPP_handleTLS: (OFXMLElement*)element;

Index: src/XMPPConnection.m
==================================================================
--- src/XMPPConnection.m
+++ src/XMPPConnection.m
@@ -49,10 +49,12 @@
 #import "XMPPPresence.h"
 #import "XMPPMulticastDelegate.h"
 #import "XMPPExceptions.h"
 #import "XMPPXMLElementBuilder.h"
 #import "namespaces.h"
+
+#import <ObjFW/macros.h>
 
 @implementation XMPPConnection
 + connection
 {
 	return [[[self alloc] init] autorelease];
@@ -526,10 +528,12 @@
 	}
 }
 
 - (void)XMPP_startStream
 {
+	OFString *langString = @"";
+
 	/* Make sure we don't get any old events */
 	[parser setDelegate: nil];
 	[elementBuilder setDelegate: nil];
 
 	/*
@@ -542,16 +546,21 @@
 	parser = [[OFXMLParser alloc] init];
 	[parser setDelegate: self];
 
 	elementBuilder = [[XMPPXMLElementBuilder alloc] init];
 	[elementBuilder setDelegate: self];
+
+	if (language != nil)
+		langString = [OFString stringWithFormat: @"xml:lang='%@' ",
+							 language];
 
 	[sock writeFormat: @"<?xml version='1.0'?>\n"
 			   @"<stream:stream to='%@' "
 			   @"xmlns='" XMPP_NS_CLIENT @"' "
-			   @"xmlns:stream='" XMPP_NS_STREAM @"' "
-			   @"version='1.0'>", domain];
+			   @"xmlns:stream='" XMPP_NS_STREAM @"' %@"
+			   @"version='1.0'>", domain, langString];
+
 	streamOpen = YES;
 }
 
 - (void)close
 {
@@ -1039,10 +1048,20 @@
 
 - (uint16_t)port
 {
 	return port;
 }
+
+- (void)setLanguage: (OFString*)language_
+{
+	OF_SETTER(language, language_, YES, YES)
+}
+
+- (OFString*)language
+{
+	OF_GETTER(language, YES)
+}
 
 - (void)addDelegate: (id <XMPPConnectionDelegate>)delegate
 {
 	[delegates addDelegate: delegate];
 }

Index: src/XMPPStanza.h
==================================================================
--- src/XMPPStanza.h
+++ src/XMPPStanza.h
@@ -33,10 +33,11 @@
 /// \cond internal
 	XMPPJID *from;
 	XMPPJID *to;
 	OFString *type;
 	OFString *ID;
+	OFString *language;
 /// \endcond
 }
 
 #ifdef OF_HAVE_PROPERTIES
 /// \brief The value of the stanza's from attribute
@@ -45,10 +46,11 @@
 @property (copy) XMPPJID *to;
 /// \brief The value of the stanza's type attribute
 @property (copy) OFString *type;
 /// \brief The value of the stanza's id attribute
 @property (copy) OFString *ID;
+/// \brief The stanza's xml:lang
 #endif
 
 /**
  * \brief Creates a new autoreleased XMPPStanza with the specified name.
  *
@@ -156,6 +158,8 @@
 - (XMPPJID*)to;
 - (void)setType: (OFString*)type;
 - (OFString*)type;
 - (void)setID: (OFString*)ID;
 - (OFString*)ID;
+- (void)setLanguage: (OFString*)language;
+- (OFString*)language;
 @end

Index: src/XMPPStanza.m
==================================================================
--- src/XMPPStanza.m
+++ src/XMPPStanza.m
@@ -209,21 +209,42 @@
 	return [[type copy] autorelease];
 }
 
 - (void)setID: (OFString*)ID_
 {
-	OFString* old = ID;
+	OFString *old = ID;
 	ID = [ID_ copy];
 	[old release];
 
 	[self removeAttributeForName: @"id"];
 
 	if (ID_ != nil)
 		[self addAttributeWithName: @"id"
-			       stringValue: ID];
+			       stringValue: ID_];
 }
 
 - (OFString*)ID
 {
 	return [[ID copy] autorelease];
 }
+
+- (void)setLanguage: (OFString*)language_
+{
+	OFString *old = language;
+	language = [language_ copy];
+	[old release];
+
+	[self removeAttributeForName: @"lang"
+			   namespace: @"http://www.w3.org/XML/1998/namespace"];
+
+	if (language_ != nil)
+		[self addAttributeWithName: @"lang"
+				 namespace: @"http://www.w3.org/XML/1998/"
+					    @"namespace"
+			       stringValue: language_];
+}
+
+- (OFString*)language
+{
+	return [[language copy] autorelease];
+}
 @end