Ragnarok is no ghost server!
The population is obviously lower than on other servers but you won't notice that because during European main playing time (evening) there are A LOT of players online, doing all kinds of stuff and a whole lot is going on
Most people on Ragnarok speak English but - like on any other server - there will be some players who are bad at it or don't speak it at all.

If you are only able to play in the morning or really late at night (like 3 or 4 am) a different server might be better for you though because not much is happening on Ragnarok during that time.