Hebrew is the liturgical language of Judaism (termed lashon ha-kodesh, "the holy tongue"), the language in which the Hebrew scriptures (Tanakh) were composed, and the daily speech of the Jewish people for centuries. By the fifth century BCE, Aramaic, a closely related tongue, joined Hebrew as the spoken language in Judea. By the third century BCE, Jews of the diaspora were speaking Greek. Modern Hebrew is now one of the two official languages of the State of Israel along with Arabic.
Hebrew was revived as a spoken language by Eliezer ben Yehuda, who arrived in Palestine in 1881. It hadn't been used as a mother tongue since Tannaic times. For over sixteen centuries Hebrew was used almost exclusively as a liturgical language, and as the language in which most books had been written on Judaism, with a few speaking only Hebrew on the Sabbath. For centuries, Jews worldwide have spoken the local or dominant languages of the regions they migrated to, often developing distinctive dialectal forms or branching off as independent languages. Yiddish is the Judæo-German language developed by Ashkenazi Jews who migrated to Central Europe, and Ladino is the Judæo-Spanish language developed by Sephardic Jews who migrated to the Iberian peninsula. Due to many factors, including the impact of the Holocaust on European Jewry, the Jewish exodus from Arab lands, and widespread emigration from other Jewish communities around the world, ancient and distinct Jewish languages of several communities, including Gruzinic, Judæo-Arabic, Judæo-Berber, Krymchak, Judæo-Malayalam and many others, have largely fallen out of use.
The three most commonly spoken languages among Jews today are English, modern Hebrew, and Russian, in that order. Some Romance languages, such as French and Spanish, are also widely used. Overall, the language spoken by the largest number of Jews in history is Yiddish, followed closely by English and then Hebrew. This is due to the fact that Yiddish was spoken by the majority of the world's Jews for several centuries of high Jewish populations (13 million by 1939) and because the descendents of Yiddish speakers after the Holocaust split among speaking several different languages (Hebrew, English, Russian, etc) instead of switching to only one language. If modern Hebrew and English are counted as one language, it would outnumber the total of Jews who have spoken Yiddish.
The earliest surviving Hebrew inscription, the Gezer calendar, dates from the 10th century BCE; it was written in the so-called Paleo-Hebrew alphabet (ktav ivrit), which continued to be used through the time of Solomon's Temple until changed to the new "Assyrian lettering" (ktav ashurit), the "square-script", by Ezra the Scribe following the Babylonian Exile. During this time there were also changes in the language, as it developed towards Mishnaic Hebrew. Until then, most Jews had spoken Hebrew in Israel and Judea, however, by the destruction of the Second Temple, most had already shifted to speaking Aramaic, with a significant number in the large diaspora speaking Koine Greek. To cater for their needs, the Bible had been translated into the Aramaic Targum and the Greek Septuagint. As Jews emigrated to far-flung countries, and as the languages of the countries they were in changed, they often adopted the local languages, and thus came to speak a great variety of languages. During the early Middle Ages, Aramaic continued to be the principal Jewish language. Most of the Talmud is written in Aramaic. Rashi wrote in the French language of his day. Later in the Middle Ages, most Jewish literary activity was carried out in Judæo-Arabic, which was Arabic written in the Hebrew alphabet; this is the language Maimonides wrote in.
Hebrew itself remained in vigorous use for religious and official uses such as for all religious events, Responsa, for writing Torah scrolls, and along with Aramaic, retained a position of importance for the writing of marriage contracts and other literary purposes.
As time passed, these Jewish dialects often became so different from the parent languages as to constitute new languages, typically with a heavy influx of Hebrew and Aramaic loanwords and other innovations within the language. Thus were formed a variety of languages specific to the Jewish community; perhaps the most notable of these are Yiddish in Europe (mainly from German) and Ladino (from Spanish), originally in al-Andalus but spreading to other locations, mainly around the Mediterranean, due to the 1492 expulsion of practicing Jews from Spain and the persecution by the Inquisition of the conversos.
Jews in the diaspora have tended to live in segregated communities. This segregation was partly enforced on them by the wider communities, and partly by choice in an endeavor to maintain their own culture. These sociological factors contributed to the formation of dialects that often developed and diverged to form separate languages.
At the beginning of the nineteenth century, Yiddish was the main language of Jews in Eastern Europe (thus making it the language spoken by the majority of Jews in the world), while Ladino was widespread in the Maghreb, Turkey, Bulgaria and Greece; smaller groups in Europe spoke such languages as Judæo-Italian, Yevanic, or Karaim. The Jews of the Arab world spoke Judæo-Arabic varieties, while those of Iran spoke Dzhidi (Judæo-Persian); smaller groups spoke Judæo-Berber, Judæo-Tat or even, in Kurdistan, Judæo-Aramaic. The Beta Israel were abandoning their Kayla language for Amharic, while the Cochin Jews continued to speak Malayalam.
Jews today speak a large variety of languages, typically adopting the languages of their countries of residence. The largest single language spoken by Jews is English: The second largest Jewish population in the world is in the United States, and there are also large, substantial communities in Canada (a majority of Canadian Jews speak English, not French), the United Kingdom, Australia, and South Africa. Ireland and New Zealand also have small Jewish communities which speak predominantly English.
English is closely followed by Modern Hebrew, the spoken language in Israel, and by Israeli emigrants who live in other countries. Hebrew is the language of daily life in Israel, though a substantial proportion of the country's citizens are immigrants who speak it as their second language.
After English and Hebrew, the next largest language spoken by large populations of Jews is Russian, with perhaps two million speakers from the former Soviet Union, a majority of whom now live in Israel. Approximately 1 million Israelis speak Russian fluently.
French, Spanish, and Portuguese constitute the final "tier" of languages spoken by major Jewish populations. French is spoken by hundreds of thousands of Jews in France and Quebec, most of them immigrants from North Africa who originally spoke Arabic. Spanish and Portuguese are spoken by large Jewish communities in Central and South America; Buenos Aires has a large Jewish community. A substantial number of current immigrants to Israel speak French or Spanish as their mother tongue.
Yiddish continues to be spoken by older generations of Jews, as well as in Haredi communities. Although the number of older speakers is continually decreasing, there is revived interest in Yiddish in academia and the arts, and the populations of Yiddish-speaking Hasidic communities are showing trends in growth.
Thus Yiddish, once the language of the majority of the world's Jews, continues to be spoken, as are nearly all the languages discussed in the preceding section. However, some of these languages, notably Judæo-Aramaic, are considered to be gravely endangered.
Conversely, Ladino is usually written in Turkey in the Latin alphabet with a spelling similar to that of Turkish, and has been occasionally printed in Greek and Cyrillic alphabets.
Soviet authorities tried to promote the Cyrillic alphabet for Yiddish in the Jewish Autonomous Oblast.
Also, some Yiddish-speakers have adopted the use of the Latin alphabet, in place of the Hebrew alphabet. This is predominantly to enable communications over the internet, without the need for special Hebrew keyboards.