The Grimm brothers: Rockstar linguists (1822)
Jacob Grimm (1785–1863) and Wilhelm Grimm (1786–1859) are known to the whole world as the collectors of Snow White, Rapunzel and Hansel and Gretel. In the history of science, however, the brothers from Hanau are something else entirely: founders of Germanic philology and pioneers of historical linguistics. In 1822 Jacob formulated what is still called Grimm’s law — the first systematically described sound change in the history of linguistics, the demonstration that languages do not decay randomly but change according to regularities you can state, test and use.
And the “rockstar” part is not just a joke in the title. The Grimms were genuine celebrities of the nineteenth century: authors of some of the best-selling books ever printed, political heroes fired from their professorships for defying a king, and scholars so famous that Germany later put their portrait on the 1,000-mark banknote. Very few linguists get a law of nature named after them; fewer still get onto money.
Grimm’s law (1822): the sound shift that made language change a science
In the second edition of the first volume of his Deutsche Grammatik (1822), Jacob Grimm described what is now called the First Germanic Consonant Shift: at some point in prehistory, the ancestor of English, German, Dutch and the Scandinavian languages transformed a whole series of Indo-European consonants — not word by word, but as a system. Voiceless stops became fricatives (p → f, t → þ, k → h), voiced stops became voiceless (b → p, d → t, g → k), and aspirated stops lost their aspiration (bʰ, dʰ, gʰ → b, d, g). Latin, which did not undergo the shift, preserves consonants close to the older state — which is why Latin and English cognates line up so neatly:
| Shift | Latin (unshifted) | English (shifted) |
|---|---|---|
| p → f | pater, pes | father, foot |
| t → þ (th) | tres, tu | three, thou |
| k → h | centum, cornu | hundred, horn |
| d → t | duo, decem | two, ten |
| g → k | genu, granum | knee, corn |
| bʰ, dʰ, gʰ → b, d, g | frater, foris, hostis | brother, door, guest |
In the same work Grimm also described a second shift that later affected High German only: p → pf/f, t → ts/s, k → ch. That is why English and Dutch agree with each other against German: apple/appel vs Apfel, water/water vs Wasser, make/maken vs machen.
The revolutionary point was not any single etymology but the claim of regularity: if p became f, it did so across the entire vocabulary, under statable conditions. A resemblance like pater–father stopped being a curiosity and became evidence. With Grimm’s law, statements about the prehistory of languages could be wrong — and therefore, for the first time, they could also be right. That is the moment historical linguistics became a science.
Rask, Grimm and the comparative method
Honesty requires saying that Jacob Grimm was not the first to see the correspondences. The Danish linguist Rasmus Rask, in a prize essay written in 1814 and published in 1818, had already laid out the systematic consonant correspondences between Germanic and the other Indo-European languages, including Greek and Latin. Grimm read Rask and said so. What Grimm added — and what justified attaching his name to the law — was scale and system: he presented the correspondences as one complete, ordered chain shift covering the whole consonant inventory, embedded in a four-volume grammar of the entire Germanic language family, from Gothic to his own German.
Together, Rask’s and Grimm’s work established the comparative method: compare related languages systematically, find the regular sound correspondences, and use them to reconstruct the unattested ancestor language. It remains the core method of historical linguistics two centuries later — the same logic by which Ferdinand de Saussure would later predict, on paper, sounds of Proto-Indo-European that were only confirmed decades after his death.
The fairy tales and the Wörterbuch: philology by other means
The famous tales belong to the same scholarly project. The Grimms collected the Kinder- und Hausmärchen (first volume 1812, second 1815) not primarily as children’s entertainment but as documentation: they believed the oral tales of ordinary people preserved ancient Germanic language, poetry and myth that written literature had lost, and they annotated the tales like the philologists they were. The collection grew to over 200 stories, became — after the Bible — one of the most widely read German books in history, and incidentally gave language learners a gift that keeps on giving: stories almost everyone already knows in their own language, which makes them unusually easy to read in a foreign one.
The brothers’ second monument is the Deutsches Wörterbuch, the great historical dictionary of German, which they began in 1838 after being expelled from their Göttingen professorships — two of the “Göttingen Seven” professors dismissed in 1837 for publicly protesting the King of Hanover’s abolition of the constitution (the episode that made them political celebrities across Germany). The first volume appeared in 1854. Wilhelm completed the letter D and died in 1859; Jacob worked on until 1863, dying while writing the entry Frucht (“fruit”). Generations of scholars carried the dictionary on, and it was finished only in 1961 — 123 years and 32 volumes after it began, still the largest dictionary of German ever made and freely searchable online today.
The legacy: Verner’s law and the Neogrammarians
Grimm knew his law had exceptions and was untroubled by them — “the sound shift succeeds in the main,” he wrote. The exceptions turned out to be the most productive part. In 1875 the Danish linguist Karl Verner showed (in a paper published in 1876) that a whole class of them was itself perfectly regular: where Grimm’s law seemed to fail — Latin pater giving Gothic fadar with d instead of the expected þ — the outcome depended on where the word’s accent had fallen in Proto-Indo-European. An apparent hole in one law was plugged by discovering another, deeper one.
Verner’s result electrified the young Leipzig linguists soon known as the Neogrammarians, who in the late 1870s raised it to a manifesto: sound laws admit no exceptions — apparent exceptions are unrecognized laws or borrowings. That uncompromising principle powered the golden age of historical linguistics, produced the reconstruction of Proto-Indo-European, and trained the generation — Saussure among them — that went on to build modern linguistics. The line from a Kassel librarian’s grammar to twentieth-century structuralism is direct.
What this means for learning a language
Grimm’s law is not just history — it is a practical decoding tool for anyone learning German or Dutch from English (or the reverse), because the correspondences it describes are still sitting in today’s vocabulary. A handful of patterns unlocks hundreds of words:
- English th ↔ German/Dutch d: three–drei–drie, thing–Ding–ding, thick–dick–dik;
- English p ↔ German pf/f (Dutch keeps p): apple–Apfel–appel, pepper–Pfeffer–peper, ship–Schiff–schip;
- English t ↔ German s/z (Dutch keeps t): water–Wasser–water, eat–essen–eten, two–zwei–twee;
- English k ↔ German ch (Dutch keeps k): make–machen–maken, book–Buch–boek.
Treat these as a mnemonic, not as a rule to compute in real time: when you meet Zahn or tand, the correspondence whispers “tooth”, and the word anchors itself to something you already know instead of floating free. That is exactly how memory works best — new items attached to old ones. It also explains why German and Dutch feel so guessable to English speakers once you know a few systematic patterns rather than lists of rules, and it pairs naturally with a phonetic alphabet when you want to see the sounds behind the spellings. None of this replaces actually acquiring the language — recognizing Wasser is not the same as using it in a sentence, which is why cognate-spotting works best inside a structured approach to learning German built on hearing and producing whole sentences.
FAQ
What is Grimm’s law in simple terms?
It is the observation that the Germanic languages, at some prehistoric stage, shifted a whole set of consonants in a regular way: p, t, k became f, th, h; b, d, g became p, t, k; and the old aspirated stops became b, d, g. That is why Latin pater corresponds to English father and Latin duo to English two. Jacob Grimm formulated it systematically in 1822.
Why is it called Grimm’s law if Rask described it first?
Rasmus Rask published the key consonant correspondences in 1818, four years before Grimm, and Grimm acknowledged him. But Grimm turned scattered correspondences into a single, complete, ordered system covering the whole consonant inventory and the entire Germanic family — and it was in that form that the discovery changed linguistics. Many historians compromise by calling it the Rask–Grimm rule.
How long did the Grimms’ German dictionary take to finish?
123 years. The brothers began the Deutsches Wörterbuch in 1838; the first volume appeared in 1854; Wilhelm died in 1859 and Jacob in 1863, having reached the entry Frucht. Later scholars and academies completed the 32-volume work in 1961, and it remains the largest dictionary of the German language.
Sources
- “Brothers Grimm”, Encyclopaedia Britannica.
- “Grimm’s law”, Encyclopaedia Britannica.
- “Deutsche Grammatik”, Encyclopaedia Britannica.
- “Deutsches Wörterbuch von Jacob Grimm und Wilhelm Grimm”, Berlin-Brandenburgische Akademie der Wissenschaften.
- “K. Verner”, A Reader in Nineteenth-Century Historical Indo-European Linguistics, Linguistics Research Center, University of Texas at Austin.