If you don't speak Thai and get a message like "the Thai news page is totally bonkers," you won't be able to help troubleshoot very easily since it may be difficult to even find that page. If you have multiple timezones that you're dealing with, you could waste time getting clarifications/etc about which page it is they are talking about (of course a URL + screenshot + indication of exactly what's wrong would be great in the first place, but upset users often don't send this level of detail). Being able to search the Thai site in the backend on "news" may allow you to quickly find that page for troubleshooting.
If you have a large site with lots of languages, you may have one common language that all of the institution's staff knows. For instance, English might be the institutional working language. In that case, it might be best to always require an English title in addition to the actual title of a piece of content.
Of course, if you always had an English version of every piece of content, then you could just use that English version for back end administration. But chances are you will have content that is just in a non-English piece of content. In that case, having all non-English content tagged with an English title could be helpful (which could automatically get set to the existing title of the English version of the content if the English version exists).
Also, you should probably decide early on if you're going to have other backend features in English or in the different languages. For example, if you have a common institutional working language, then you should probably have all the names of the sites in the administrative backend in English in addition to the site's actual title in the site's language.
