My suggestion for anyone looking to invest in domains in another language is that your are at least semi-fluent and familiar with the culture of the 2nd domain language you invest in.
Why?
1. Proper spelling
2. Proper meaning
3. Understanding culture helps understand target markets and audiences
4. If your domain is in another language, you may get a buyer contacting you that doesn't speak english. It's important you can communicate with them. (Automated translators won't cut it)
5. You have to be able to read another language to research and find a potential buyer in that language
There's many more reasons, i'm sure, however the above are just off the top of my head at the moment. You definitely don't want to be investing in domains you have no clue how to find or communicate with buyers for. It's hard enough finding buyers sometimes in ones native language, so I'm sure you can imagine how hard it may be if its in a language you don't understand.
I'm sure you could possibly hire someone that's bi-lingual, but then you have to be sure they actually qualify with the above listed too, and that you're ok with giving them a portion of your profits (if any). Even with a broker, the initial research of buying the domain for resell purposes starts with you, so you still need to understand the language and culture to do that adequately.
And yes, I understand that there's a few lucky situations where a common non-english word sold and the owner didn't know what it even meant, but I wouldn't count on that happening with better odds than the lottery.
Just my thoughts anyways,
Eric Lyon