Although Jesus and His disciples spoke a dialect of Aramaic known as Old Galilean, we do not have any surviving manuscripts of the New Testament in the Old Galilean. The closest we have are a few manuscripts of the New Testament in the Syriac, a dialect of the Old Galilean Aramaic.
The Syriac is the closest to the Old Galilean we have in the New Testament today, yet it is not entirely the same as the Old Galilean. It is sort of like the difference between the English spoken in Australia and the United States.
Despite the differences in idioms and colloquial expressions with words totally unknown in the American English language, it is still English, only with a different dialect. Yet, there is no reason an American citizen would not be able to effectively carry on a meaningful conversation with a native-born Australian. It is pretty much the same with the various dialects of Aramaic. However, there is always the danger of error and mistranslation.
Although we know very little at this time about the Old Galilean dialect of Aramaic, we do understand many other dialects of Aramaic, particularly the Syriac, which has a version of the New Testament and some ancient documents to support the present Aramaic Bible known as the Peshitta.
Most Biblical scholars believe that the inspired text of the New Testament was written in the Greek and not the Aramaic, although they do agree that the language Jesus spoke was Aramaic. The Eastern church, however, believes that the inspired text of the New Testament was in Aramaic.
This writer holds the position that the inspired text of the New Testament was in Koine Greek, but that the language spoken by Jesus, His disciples, and the Apostle Paul was Aramaic and that many words in the New Testament were dictated by the disciples and Paul in Aramaic to a scribe who translated these words into Greek. When you translate from Aramaic into Greek, you do have problems finding a proper Greek word to fit the Aramaic word. For instance, the Word agape is used for racham. Yet, agape does not fully express the nature of racham. When Jesus spoke with Peter, he asked Peter if he agape Him. In the Aramaic, the word racham is used, which is the best Greek word to use for racham, but it is hardly a cognate of the word racham.
I write this book praying that my readers do not use the Aramaic as the final word but as a source to lead them to a deeper understanding of many of the problem passages that we have in the New Testament. It is the Holy Spirit who leads us into all truth and anything shared in this book should ultimately be considered in the words of Colossian 3:15: "And let the peace of God rule in your hearts, to the which also ye are called in one body; and be ye thankful."