elgg_echo($message_key, $args=array(), $language="")
Given a message key, returns an appropriately translated full-text string.
elgg_extract($key, $array, $default=null, $strict=true)
Checks for $array[$key] and returns its value if it exists, else returns $default.
elgg_get_page_owner_guid($guid=0)
Gets the guid of the entity that owns the current page.