Yes, Sanskrit is spoken not only on Krishna Loka but also in higher planets, of the demigods. It is called the language of God and the demigods. It was spoken also on this planet, when people were all godly, they used to speak in Sanskrit. Sanskrit is the origin of all languages of the civilized peoples. It is most perfect, not only descriptive; the word "Sanskrit" means "the most perfect". Because not a single word you can pronounce without having a bona fide principle. It is not like the English language, "but, put" with irrational difference in pronunciation, no principles. Sanskrit isn't like that. Therefore it is perfect. It isn't whimsical. English poetry has one line one inch long, next line 600 inches long. Sanskrit is not like that. There are strict principles, and it is so beautiful. Therefore in Sanskrit language not an ordinary man can become a poet. No other language of the world can be compared with it. No other language of the world is so perfect as Sanskrit. Any language near to Sanskrit language (like Bengali) is nearer to perfection. Sanskrit is pronounced same way here or there, it is standard.
Yes you can sing prayers in Sanskrit, but prayers in English can be also pronounced because the Lord accepts the motive not the pronunciation of the language. He wants to see spiritual motive. Even if some effectiveness is lost in translation, if the motive is there, it will make no difference.