Lasch was born into a family of Jewish merchants in 1879. Like her three sisters, she first trained as a teacher (1898) and then taught at various girls' schools and vocational schools until 1906. In 1906 she received her
Abitur from the
Kaiserin Augusta Gymnasium in
Charlottenburg (Berlin). After this she was able to study German in
Halle and then at
Heidelberg under the supervision of
Wilhelm Braune, and received her doctorate in 1909, despite the fact that as a woman she was not permitted to attend courses in Berlin in 1908. Because of her impressive achievements she was offered a job as Associate Professor at the women's liberal arts college
Bryn Mawr in
Pennsylvania. Here she produced her Middle Low German grammar around 1914, which is still a standard reference work in Germanic linguistics today. Due to the USA's entry into the
First World War, Lasch returned to Germany in 1917 to take up a post as Assistentin in German at Hamburg. Following her
habilitation (1919), in 1923 she was the first woman to receive the title of professor at the University of Hamburg, and the first female Germanist to receive this title in all of Germany. In 1926 an extraordinary chair in Low German philology was created for her at Hamburg. There, Lasch continued the study of the linguistic history of Berlin that had begun in her dissertation, and published these in 1928 in her book
Berlinisch. In addition, she worked with
Conrad Borchling on two large dictionary projects to systematically capture the lexicon of Middle Low German and of the
Hamburgisch dialect. In 1928 she was able to publish the first volume of her Middle Low German dictionary (). The dictionary of Hamburgisch only started to appear in 1956 on the basis of her preparations. Researchers from abroad were briefly able to prevent her being dismissed immediately once the
Nazi Party came to power, but in 1934 she was nevertheless stripped of her professorship. In 1937 she moved to Berlin to live with her sisters and attempted to continue her research. She was banned from publishing, and was no longer allowed to use public libraries. In addition, on 8 December 1938, Jewish researchers lost their previous special right to use university libraries. Her own library of around 4,000 volumes was seized and confiscated on 9 July 1942. The German government prevented her from taking up job offers at universities abroad (
Tartu and later
Oslo). On 13 August 1942 she and her sisters were ordered to a
concentration camp, and on 15 August she was
deported to
Riga. She never reached the ghetto, but was murdered on 18 August 1942 in the woods around
Šķirotava, shortly after her arrival there. ==Honours and awards==