Battalion of the Defenders of the Language
The Battalion of the Defenders of the Language () was a small but militant body established by Jewish students at the Herzliya Hebrew Gymnasium in Tel Aviv in the 1920s to urge Jews in then Mandatory Palestine to use only the Hebrew language. Formation
Many early Zionists felt that the revival of the Hebrew language was a critical part of their endeavours. By the 1920s, Hebrew was already a well-established language in Mandatory Palestine. However, with the arrival of thousands of Yiddish-speaking immigrants to Palestine as part of the Third Aliyah, many new arrivals continued to speak their native languages, such as Russian and Yiddish. The Battalion of the Defenders of the Language was formed to protect the status of the Hebrew language and promote its use among these olim. Many of the activists came from the Herzliya Hebrew Gymnasium, which had long been a centre of pro-Hebrew language activity - its alumni had organised a protest in 1913 against the use of German as the language of instruction in the newly founded Technion institute. Activities

The Battalion campaigned against the use of other languages under the slogan  (Ivri, daber ivrit; "Hebrew [i.e. Jew], speak Hebrew!") Among its most prominent supporters were  Mordechai Ben-Hillel Hacohen, a Hebrew writer, Zionist and one of the founders of Tel Aviv, and Zvi Yehuda Kook, the son of the chief rabbi Abraham Isaac Kook. The Battalion put up posters and neon signs around Tel Aviv encouraging the use of Hebrew and instructed its members to use only Hebrew in their day-to-day lives. Members of the Battalion also went out onto the streets replacing Russian and Yiddish shop signs with Hebrew ones and fixing grammatical errors in existing Hebrew signs. One member even publicly reprimanded the poet Haim Nachman Bialik for speaking Yiddish in the street. A number of members of the Battalion were involved in a march to the Western Wall in 1929, which was a pretext for the 1929 Palestine riots. Reaction 

The Jewish (mostly Yiddish) press tended to portray the group as "a gang of fanatic, insolent hoodlums". However, the battalion was seldom involved in any real violence. Ghil'ad Zuckermann has pointed out that the Battalion's efforts were concentrated exclusively against the use of non-Hebrew words, whereas they were perfectly content with words and phrases calqued into Hebrew, such as the expression  ma nishma ('How are you? ', literally 'what is heard? '), a calque from Yiddish and other European languages. See also
Hebrew language
Revival of the Hebrew language
Pro-Wailing Wall Committee
Association for Palestinian Products
War of the Languages

Notes

References
Frank, Mitch (2005). Understanding the Holy Land: Answering Questions About the Israeli-Palestinian Conflict. Viking. Meyers, Nechemia (2002). Yiddish Lives - A Language That Refuses to Die. The World and I, February 1. Segev, Tom (2000). One Palestine Complete: Jews and Arabs Under the British Mandate. Abacus. Segev, Tom (2009). When Tel Aviv was a wilderness. Haaretz, 10 May. Jewish organizations in Mandatory Palestine
Non-governmental organizations involved in the Israeli–Palestinian conflict
History of Palestine (region)
Zionism in Mandatory Palestine