Hebrew as aDead Language?

From time to time I keep hearing from certain Christian teachers that Hebrew was a dead language toward the end of the Second Temple period, that the Jews in the Diaspora had allegedly stopped using Hebrew and couldn't even read it and certainly didn't know what it meant when they saw it on the page. The reason for the translation of the Hebrew scriptures into Greek was so the Jews in the Diaspora -- who no longer read, spoke, or understood the Hebrew -- could read God's instructions and learn of their heritage in the Greek. A few centuries later, the reason for the Masoretic text and developing the vowel points in Hebrew as an indication of how words should be pronounced in Hebrew was because nobody knew what it should sound like because nobody knew how to speak the Hebrew. All of this seems wrong to me, but I need help documenting this as an error. There are several facts that cause me to conclude that the popular Christian teaching about Hebrew being a dead language and the resultant need for the Septuagint are both wrong.

1. I notice that the Ashkenazi Jews of Eastern Europe developed a language of their own called Yiddish. Yiddish is spoken by millions of Jews. Yiddish is a combination of German and Hebrew. How is it possible to combine a spoken language such as German with a dead language of any kind that results in a combination of the two languages and is spoken by millions of Jewish people?

2. I notice that the Sephardic Jews of Spain and Portugal developed a language of their own called Ladino. Ladino is spoken by millions of Jews. Ladino is a combination of Old Castilian (Spanish) and Hebrew. How is it possible to combine a spoken language such as Old Castilian with a dead language of any kind that results in a combination of the two languages and is spoken by millions of Jewish people?

3. Ashkenazi Hebrew and Sephardic Hebrew have different pronunciation patterns, but the root words and sentence structures are essentially the same. Because we have the pronunciation patterns for these two dialects of Hebrew with us today spoken by millions of Jews from their respective backgrounds, we know that Hebrew as a spoken language has never died.

4. Rabbis as early as the second century A.D. seemed to notice that Jews from different countries were pronouncing certain Hebrew words differently. The development of the vowel points by the Masoretes was an attempt to standardize the spelling and pronunciation of Hebrew between those of Ashkenazi and Sephardic background. The work of the Masoretes was not an attempt to give life to a dead language that nobody knew how to speak, but served to standardize the pronunciation patterns of Hebrew for millions of Jews who spoke the holy language in two different dialects in two different regions of the world.
The dictionary does the same thing for us today. Before the publication of Webster's Dictionary, English speaking people spelled words and formed certain letters in many divergent ways. The dictionary standardized the spelling of words and gives clues as to the proper pronunciation of words.

5. The Septuagint was developed as the text of scripture that Jews could share with their Gentile neighbors who were interested in learning about their God. Gentiles could not read Hebrew, but the Jews in the Diaspora were bilingual, being fluent in both Hebrew and Greek. When Alexander the Great (356 - 323) conquered Mesopotamia and other lands, and hellenized the then known world making Greek the language of civil government, he made it possible for most people in his realm to communicate in a common language. Because Greek was the common language of everyone under Greek rule, the Septuagint became the translation of the Hebrew scriptures that both Jews and Gentiles could read and understand.
Remember the Greek woman in Mark 7:26, a Syrophoenician woman by race. She must have had a Jewish friend who taught her about the God of Abraham so that when Yeshua arrived with His disciples, she was eager to seek a blessing from Him as a faithful believer. Remember that the Jewish leaders in John 7:35 wondered if Yeshua was planning to go to the Diaspora to teach the Greeks. What point would there be in teaching the Greeks if there were not some of them who were already familiar with the God of Abraham through the Septuagint? This familiarity would only develop through the ordinary friendships of Jews with their Gentile neighbors and the opportunity for the Gentiles to read in their own language the record of the workings of the God of heaven. Remember that there were Greeks who came to worship in Jerusalem at the time of Passover and the Feast of Unleavened Bread in John 12:20-21. They came to Philip and said, "Sir, we want to see Yeshua." These were not sightseers, neither were they escorted to Jerusalem by Jews. These Greeks came to Jerusalem for the purpose of worship. The decision to come to Jerusalem to worship could have occurred only if they had been exposed to the history of God's dealing with His chosen people and the invitation for the Greeks to join His people in the most solemn and joyous acts of worship at the Lord's appointed festival. The prophecies of the coming Messiah were taught to these Greeks along with the notion that Yeshua was the fulfillment of the messianic prophecies as evidenced by their request to see Yeshua. These Greeks could not have studied the messianic prophecies for themselves without the Septuagint. Rather than the Septuagint being the only scriptures the Jews in the Diaspora could read because they were no longer fluent in Hebrew, the Septuagint was primarily an evangelistic tool for the Jews in the Diaspora to share the God of heaven with their Greek neighbors.

6. The only way a new language, such as either Yiddish or Ladino, can develop is when both languages are spoken and understood by those who develop the third language. Spanglish is an example. While Spanglish is not a fully developed language of its own, Spanglish is the result of people who are fluent in both Spanish and English and who find it convenient to blend certain words and rules of grammar and speech from both languages in their communications with others with a similar background. Spanglish could never come into existence if either Spanish or English were a dead language.

7. Until just a few decades ago, the Catholic Church held its services in Latin -- a language few of the members of the Catholic Church outside the priests and monks understood. Latin is a dead language and has been for several centuries, Italian having replaced Latin as the spoken language of the Italians in the early 14th century. I am not aware of any languages that have developed from Latin and some other language native to a particular country. Citing Latin as a dead language that was used only in religious services as an example of how dead the Hebrew language had become except in religious services is contradicted by the cultural evidence of Ashkenazi Hebrew and Yiddish in Eastern Eurpoe and Sephardic Hebrew and Ladino in Spain. The notion that Hebrew was ever a dead language seems totally without merit.

I know there is a ton of Christian writing available that says just the opposite of the understanding I've just expressed here, but I have no confidence in most of that because of the anti-Semitic bent so many Christian writers have. Do you know of any evidence in Jewish literature in support of the theory I expressed here? If so, please direct my attention to those sources. I thank you in advance for any help you can give me.

Cordially,

Jerry