A problem when changing the language There's is a problem when changing the language  on my MacBook Air, if I need to change the language I have to press ⌘+space not once, but I have to press it twice if I need to change the language from English to Arabic!

How can I fix this so I only have press it once?
You might be able to fix the problem by going into system preferences > keyboard > shortcuts, and find out if any other keyboard shortcuts using ⌘+space. I know that ⌘+space is used for the spotlight search or Siri by default on my mac. you could try disabling Siri and see if that fixes the problem.