Most German vocabulary is derived from the Germanic branch of the Indo-European language family, although there are significant minorities of words derived from Latin and Greek, and a smaller amount from French and most recently English. At the same time, the effectiveness of the German language in forming equivalents for foreign words from its inherited Germanic stem repertory is great. Thus, Notker Labeo was able to translate Aristotelian treatises in pure (Old High) German in the decades after the year 1000. Overall, German has fewer Romance-language loanwords than English or even Dutch.

Even today, some low-key non-academic movements try to promote the Ersatz (substitution) of virtually all foreign words with ancient, dialectal, or neologous German alternatives. It is claimed that this would also help in spreading modern or scientific notions among the less educated, and thus democratise public life, too.

The modern German scientific vocabulary has nine million words and word groups (based on the analysis of 35 million sentences of a corpus in Leipzig, which as of July 2003 included 500 million words in total).
