Importance of a Steemit Post Language

Friends today I have a question in my mind, what is it necessary that all our posts must shoud be in english language or can we use any other language on steemit?

WHAT IS YOUR STEEMIT POST LAUGAUGE

At the beginning when I joined steemit I thought it is only english medium platform, but gradually when my followers increased I saw many posts in other languages like Dutch, Spanish. Then I focused whether posts in other languages have earnings, comment and upvotes like english posts or not. There were a bit difference in earning but there are many posts in other languages which earned a lot.

So, i want to know how much a language is important on steemit? can we earn by writing in other language than english as there are many users from different countries.

please kindly gives your valuable suggestions knowledge base comments regarding this matter.