There is no need to take Ibn Arabi seriously either. He has said stuff which has harmed the foundations of Islam and this one ie "Imam Mehdi does not speak Arabic well" is of trivial importance when compared with the other deviations he tried to induct into Islam. He has been declared a disbeliever by Shaykh ul Islam Ibn Taymiyyah ra , Imam Al Dhahabi , Imam Ibn Kathir , Imam Ibn Rajjab al Hanbali and many other scholars.