diff --git a/AFNetworking/AFHTTPClient.m b/AFNetworking/AFHTTPClient.m
index d9a066b..f787805 100644
--- a/AFNetworking/AFHTTPClient.m
+++ b/AFNetworking/AFHTTPClient.m
@@ -234,8 +234,13 @@ NSArray * AFQueryStringPairsFromKeyAndValue(NSString *key, id value) {
 	self.defaultHeaders = [NSMutableDictionary dictionary];
 	
     // Accept-Language HTTP Header; see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
-    NSString *preferredLanguageCodes = [[NSLocale preferredLanguages] componentsJoinedByString:@", "];
-    [self setDefaultHeader:@"Accept-Language" value:[NSString stringWithFormat:@"%@, en-us;q=0.8", preferredLanguageCodes]];
+    NSMutableArray *acceptLanguagesComponents = [NSMutableArray array];
+    [[NSLocale preferredLanguages] enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
+        float q = 1.0f - (idx * 0.1f);
+        [acceptLanguagesComponents addObject:[NSString stringWithFormat:@"%@;q=%0.1g", obj, q]];
+        *stop = q <= 0.0f;
+    }];
+    [self setDefaultHeader:@"Accept-Language" value:[acceptLanguagesComponents componentsJoinedByString:@", "]];
     
 #if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)
     // User-Agent Header; see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.43