How is Jesus God's final word? (Protestant Perspective) The Youth Catechism of the Catholic Church states plainly (emphasis added):


  In Jesus Christ, God himself came to earth. He is God's last Word.


Indeed, some modern English translations of the New Testament present Chapter titles for Hebrews 1 that echo this sentiment: God's final word: His Son (NIV), God's Final Word in His Son (NASB), God's Supreme Revelation (NKJV). Hebrews 1:1-2 says, 


  God, having spoken earlier at many times and in many ways through the Prophets, spoke to us in these last days by the Son, who he established heir over all things and through whom he made the ages.  


From a sola-scriptura protestant perspective, what does it mean that Jesus is  God's last word? Has God spoken to man in the time since Jesus' teaching? If so, by what method has he done so?
The final word refers to the final revelation, in practical terms Matthew to Revelation.  There is no Scripture after this or above it. In the past God 'gradually' over a long period revealed his word, bit-by-bit, shadow-by-shadow but when Christ came he brought the final conclusion in the gospel of grace and truth. 


  For the law was given through Moses; grace and truth came through Jesus Christ. (NIV, Jn 1:17 )


And


  In the past God spoke to our ancestors through the prophets at many times and in various ways, but in these last days he has spoken to us by his Son, whom he appointed heir of all things, and through whom also he made the universe. (NIV, Heb 1:1-2)


In the same short period he also established all remaining doctrines necessary for the church through the Apostles and forever closed up into the canon of scripture.

This final revelation was initiated at the time of Christ ending very shortly after. Its glory and superiority is based on the directness of its communication in that God himself through the incarnation spoke it to men as a man. We are not to expect any new revelation and supplemental books such as the Koran, or other books various Christian sects have claimed to have been given as a supplement in the last few hundred years.