The short answer is to not trust ANY subbers translation. Technically the "Official" English title cannot be determined until it is licensed and released in English. Until then, the best way is to go by the name in Kanji and then convert it into Romaji. If you search through the forum though you will find that there are many different opinions on how this should be done though, but in principle you should follow the
Hepburn style. If you have a question (or don't know enough to do that), you can make a post (please get the Kanji first) and then let people (Rar and rowaasr13 for the most part) make their comments. If the anime is listed on wikipedia, it can be a good source to find the Kanji and some version of the Romaji, again you can't take that for granted, but it is a start.
In this case, none of that is necessary. It has been discussed before, and the answer is at the bottom of the
page. (I guess you have already seen this.) Like it or not, until it is released in English, this would be the official name. Also if you look a
census data, Teletha is a real name (although maybe not that common).
BTW, google is another good resource, and that is how I found the answer.