Yandex Maps - it is Russian map library (API). I think it is not very usefull for internation use. Therefore there is no English translation.
For Google maps - it exists, for Baidu (Chinese Map API, will be in the future).
Today I started development for OpenStreetMaps, due to Google's policy for API (but do not stop support and development)
All of my extensions is simple to understand. If you still want to check for you Yandex Maps, just do it like in Google's documentation. All behavior and properties the same, but in Google Maps there are a lot of features, which is not implemented in Yandex Maps.
That is a disappointment. I am developing a .ru website for a Russian tourist guide and would like to incorporate Yandex Maps in the site, because Yandex is more popular in Russia than Google Maps.
Tonight we are going to work on it together; my client will have to do the translation.......... We'll see.
The extension looks very promising!
You can do trick like me when I did Zh Baidu Maps.
Google translate has ability to translate web page, just copy URL and paste into from field. And you'll get on the fly translation, and it about 90% understandable