If you want someone to follow you/be your friend, click onto their photo then click on the "Message" button that appears next to the Follow/Unfollow button. Then this message will appear: "Please write a quick introduction to yourself.
Let this person know how you can help them with your native language, and how you're interested in their language and culture!
Once this person follows you, you'll be able to send direct messages and chat"
Click 'Send' and you will be sending a follower request NOT a message. You can then message them.
HOW TO USE THE ITALKI CHAT FUNCTION
First you need to have friends. Make sure that you have the words Chat online at the right hand side of this page. Double click onto it and a list of all your friends will come up. Click onto the name of one of your friends. A little box will appear on the right hand side of your page. If there is a green light next to their name, then they are online. Type a message and press Enter on your keyboard and then and wait for their response. Type in a reply and click Enter again.