We've had customers all over the globe report success with using the HOTH in foreign countries. Our main markets are US, Austrailia, UK, but we have agencies from all over the world as clients, even in foreign language markets.
We can help you rank regardless of which flavor of Google you're using (.ca, .ie, .au, .co.uk etc).
We accept foreign keywords (the articles are still written in English, but with foreign keywords in the articles). The only thing we don't accept is non-roman characters (arabic, hebrew, chinese, etc) since it may not come out correct when we distribute articles.
We wrote a whole guide on International SEO. You can check it out here: http://www.thehoth.com/downloads/HOTH-Foreign-Keywords.pdf
Have any questions? Feel free to hit us up here: Submit a Ticket