My understanding of the Muslim belief about the Gospel of Jesus is that it has been largely lost, although pieces of it remain in the versions that modern Christians use. In what language was the Injil originally composed? Was it Hebrew? Aramaic? Perhaps Arabic?
عبرانی(Hebrew), AFAIK.– NoahJun 18, 2013 at 5:55
Jesus spoke Aramaic , yet most of the manuscripts are in greek. For an academic and detailed answer refer this book, which is the best academic book for this answer:archive.org/details/Prof.BartEhrman-MisquotingJesus– IslamJun 18, 2013 at 9:28
The Injil could have been written in Aramaic or Biblical hebrew. but when it comes to current gospel it is a set of 4 injils some written in Greek others in Aramaic and epistles. There were many Injils circulating in the first centuries of christianity the current version has been canonised almost 4 centuries later.
It is a subject of a huge debate as lutheran bible does not accept certain passages.
http://www.catholiceducation.org/articles/religion/re0134.html (from a catholic perspective)
Some of those who wrote the gospels were not even contemporaries of Jesus.
The very word "Injeel" is derived from the Greek word "evangelion" and hence it is extremely unlikely that Jesus would have used this term to describe his own book. However, if one insists that Jesus used this term, then we would have to say that Jesus probably wrote either in Greek or in a Semitic language that was strongly influenced by Greek, as is shown by the very title of the book.
I am not sure how this answers the question about the language of Injeel. No one claimed that Jesus called it injeel; he most likely called it swar, but no one knows for sure. Saying that Jesus called it injeel necessitates that its content must have been in Greek is a slippery slope fallacy in any case. Mar 10, 2018 at 19:03
Noone is saying Jesus used this specific term. It is the arabicized version of the Aramaic word for the gospel.– The ZMar 10, 2018 at 19:26
There isn't consensus that injil is is a transliteration from the greek evangelion. Islamic exegetes and linguistics have linked its etymology to النَّجْل , نَاجِلَيْه , نَجَلتُ ,النَّجَل ,التّنَاجُل (see Qurtubi, Razi, Ibn Manzur etc.)– UmHMar 11, 2018 at 8:20