The English half of the sign is printed correctly and says, “No entry for heavy goods vehicles. Residential site only.” Clearly enough, the point of the sign is to prohibit truck drivers from entering a residential neighborhood.
Since the sign was posted in Swansea, Wales, the bottom half of the sign is written in Welsh. The translation of the Welsh is, “I am not in the office at the moment. Send any work to be translated.”
For explanation, see The Case of the Welsh Autoresponder at Revealing Errors, an awesome blog.