What is the language in which people will be addressed in al-Barzakh?
Question

                Many languages are spoken world wide. what will be the language to ask questions by angles in grave that, everybody can reply?.
Praise be to Allah.
    We have found three opinions concerning this issue. 

    1 – That they will be questioned in Syriac. 

    This was the view of al-Balqeeni, as was narrated from him by 
    his student al-Suyooti in his essay Sharh al-Sudoor fi Ahwaal al-Mawta 
    wa’l-Quboor – but he did not give any reliable evidence for that. 

    2 – That they will be questioned in Arabic. 

    This was stated by al-Haafiz Ibn Hajar (may Allaah have mercy 
    on him). Evidence of that may be seen in the apparent meaning of the 
    ahaadeeth, because they describe what will happen in al-Barzakh in Arabic, 
    and there is no reason why this should not be true, and Allaah will inspire 
    everyone who is tested in the grave so that he will understand this language 
    and answer in it. 

    Ibn Hajar (may Allaah have mercy on him) said: 

    With regard to the questioning by the two angels, the 
    apparent meaning of the saheeh hadeeth is that it will be in Arabic, because 
    it says that they will say to him: “What do you know about this man?” etc. 
    However it may also be understood as meaning that each person will be 
    addressed in his own language. End quote. 

    Al-Imtaa’ bi’l-Arba’een al-Mutabaayinatu’l-Samaa’ 
    (p. 122). 

    3 – That he will be questioned in a language that he 
    understands. 

    This was mentioned by Ibn Hajar as a possibility, as stated 
    above. 

    This was also stated in fatwas by the Standing Committee, and 
    by Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on them). 

    It says in Fataawa al-Lajnah al-Daa’imah (3/450): When 
    a person dies and is buried, two angels come to him and ask him about his 
    Lord, his Prophet and his religion in a language that he understands. End 
    quote. 

    Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said: 

    One of the scholars said: He will be questioned in Syriac. 
    Subhaan-Allaah! Syriac is the language of the Christians. It seems – and 
    Allaah knows best – that this idea was taken from the Christians, so that 
    they could boast and say, Our language is the language of questioning in the 
    grave for everyone who dies. 

    What appears to be the case is that he will be questioned in 
    whatever language he understands. If he is an Arab then he will be 
    questioned in Arabic and if he is a non-Arab then he will be questioned in 
    his own language. End quote. 

    Sharh al-‘Aqeedah al-Safaareeniyyah 
    (p. 435), Dar al-Watan. 

    In our opinion it is better to refrain from commenting on 
    that because there is no saheeh text on this issue, and concerning oneself 
    with these details is something which will not benefit the questioner in 
    either religious or worldly terms. It is sufficient for him to believe that 
    he will be questioned in his grave, and to ask Allaah to help him to obey 
    Him and to inspire him with the right answers, and to make him steadfast 
    when he is questioned. 

    Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) 
    was asked the following question: 

    How will the people be addressed on the Day of Resurrection? 
    Will Allaah address them in Arabic? Is it true that the language of the 
    people of Hell will be Farsi and that the language of the people of Paradise 
    will be Arabic? 

    He (may Allaah have mercy on him) replied: 

    It is not known which language the people will speak on that 
    Day or in which language they will hear the words of the Lord, may He be 
    glorified and exalted, because Allaah has not told us anything about that, 
    and neither has His Messenger  (peace and blessings of Allaah be upon 
    him). It is not true that Farsi is the language of the people of Hell or 
    that Arabic is the language of the people of Paradise. We do not know of any 
    dispute concerning that among the Sahaabah (may Allaah be pleased with 
    them); rather they all refrained from discussing that, because discussing 
    such matters is unnecessary talk. But there was a dispute concerning that 
    among later scholars. 

    Some people said that they will speak  in Arabic, and others 
    said: Except the people of Hell, who will answer in Farsi, which will be 
    their language in Hell. Others said: They will be speak in Syriac, because 
    it is the language of Adam, and from it all other languages stemmed. Others 
    said: Except the people of Paradise, who will speak Arabic. 

    None of the proponents of these arguments have any evidence, 
    whether based on reason or textual evidence. Rather they are claims that are 
    devoid of any evidence. Allaah knows best and is Most Wise. End quote. 

    Majmoo’ al-Fataawa (4/300). 

    And Allaah knows best.