Or you need ot not take a lack of reply to heart, and stop assuming people have to talk to you. English is in high demand, and I get tons of messages asking to chat. 

Not responding is not a lack of respect. There are 2 buttons next to a friend request: Accept and Ignore. If someone does not want to accept , you push the Ignore button. Many people have "Ignored " me and I am not offended. I am offended by people wasting my time or sending rude messages. 
Responding to each message is easy if you only get a few, but if you get 50 a day it is hard, and there is no way to tell who is serious.
I have found if I do respond in any way people are more likely to continue messaging me or start harassing me.other reasons for ignoring it could be: don't have time, not the language the are learning, or For example I cant voice-chat but that is what almost everyone wants.

It is simple, don't message them. Message just people who want to learn Arabic. In some materialistic cultures, there is no such thing called respect.There is just give to take. That's it.

@Comandante many people on this website volunteer their time to help people learning English (and other languages) and do not get anything in return.

@merlyn: Yes, and my comment not for those people who spend their time to help the other people. My comment is clear, I told him not to message anyone. Jest people who are learning his native language. So, he can give in return.