Grimm's Law

Grimm's Law is a pattern of changes in Germanic languages. Those changes all occurred in pre-history but left evidence today.

It is Grimm's because one of the Brothers Grimm of fairytale fame discovered it (Rasmus Rask discovered it a bit earlier and Grimm built on Rask's analysis).

It is a "law" more like the law of gravity is a law than like the law against murder.

The hypothesized ancestor of the Germanic language family, called "Proto-Germanic," developed from an earlier proto-language, Proto-Indo-European. Part of the development from Proto-Indo-European to Proto-Germanic was that certain sounds "shifted."

A sound shift occurs when 1) phoneme a shifts to phoneme b, and 2) every word that includes phoneme a (in similar situations in words) stops being pronounced with phoneme a and comes to be pronounced with phoneme b.

A phoneme is the smallest sound in a language that can carry meaning: note that it does not have to carry meaning. It just has to be able to carry meaning. Consider /z/, the phoneme that makes "phonemes" different in meaning from "phoneme": the phoneme /z/ does not mean anything by itself, but it can when combined in an acceptable way with a morpheme (morpheme being the smallest unit in a language that does carry meaning).

So it's a specific phoneme that shifts over to another phoneme, and it happens universally in the language.

Note that the shifts we are going to talk about here occurred in pre-history, and only the words of Old English and other old Germanic languages show its effects. In other words, it is "hypothetical."

If you harbor any lingering doubts about the reality of Indo-European reconstruction, now is one of those times to voice those doubts. This ought to convince you that reconstruction is at least highly plausible.

In some cases, Modern English includes many examples of descendants of the same Proto-Indo-European root word in different forms, some of which underwent these shifts, others of which did not. Of those that underwent these shifts, all were old Germanic language words. Those that did not undergo those shifts came into English from non-Germanic languages (i.e. they are borrowings rather than changes). Some underwent further changes, while some did not.

There are three phases to the shifts.

1. Voiceless stops become voiceless fricatives
2. Voiced Stops become Voiceless stops
3. Voiced aspirated stops become voiced stops

1. Voiceless stops /p/, /t/, /k/, and /kw/ become voiceless fricatives /f/, /th/, /h/ and /hw/.
   
• The voiceless stops affected are /p/, /t/, /k/, and /kw/ as in pop, tot, caulk, and quaquaversal respectively.
  
• "Stop" because they involve a stopping of the flow of air through the mouth.
• "Voiceless" because they do not involve vibration of the vocal cords.
• voiceless fricatives are /f/. /th/, and /h/ as in fiffer-feffer-feff, thin, and hi, respectively.
• "Fricatives" because they involve friction of air in a narrowed passage of the mouth.
  

PIE root	Sound Change	Modern English Derivative	Other Germanic Cognates (which show the change)	Non-Germanic Cognates (which do not show the change and reflect the  PIE) which have been borrowed into English as the words in parentheses
*ped- foot	*p > f	foot	G fuß, Du voet, Norw/Sw vot	Gk πούς, ποδ- (>E podiatrist), L pes, ped- (> E pedal), Sanskrit pad
*peku movable property		fee (< fehu)	ON fe	L pecu- (> E pecuniary)
*pur fire		fire	G feuer	Gk πῦρ (> E pyr-o-mania)
*penkwe five		five	OHG finf, ON fimmtan	Gk πέντε (> E pentagon), L quintus (> E quintet, Quentin, quintessence)
*ten stretch	*t > th	thin	ON thunnr (Mod. G goes to d: dunn)	Gk τείνειν (peritoneum, protasis, L tenu-is (> E tenuiroster), Skt tanu
*trei three		three	OHG thritto, G dritte	Gk τρίτος (> E tritium), L tres (> E trefoil), Sanskrit trayas
*kwon dog	*k > h	hound	G hund (E dachshund), Du hond (E keeshond)	Gk κύων (> E cynic), L canis (> E canine)
*kerd heart		heart	G herz, Sw hjärta	Greek kard-/card-, Latin cord-, Sanskrit syertse
*kannabis hemp		hemp	OE henep	Gk κάνναβις (> E cannabis, canvas)
*kwo relative/interrogative pronoun	*kw > hw	what	Du wat, G was, wie	L quod, quid, quam, quondam, etc. (> E quodlibet, quidnunc, quasi, quondam, etc.)
		why

These changes occurred not only when the sound was at the beginning of a word: they also occurred word-internally (with significant exceptions conditioned by stress [Verner's Law]: also, two voiceless stops in a row did not both change [eight and haft would be eighth and hafth if both had changed]; and when the voiceless stop was preceded by /s/, it did not change ([e.g. spew, stand, and scold])

ONCE THAT CHANGE HAD HAPPENED, THERE WAS A 'VACUUM' LEFT: THERE WERE NO VOICELESS STOPS--NO /p/, /t/, /k/, or  /kw/ in English!

NEXT...

2. Voiced stops /b/, /d/, /g/, and /gw/ became voiceless stops. That fills the vacuum.
   
• The voiced stops affected are /b/, /d/, /g/, and /gw/ as in bob, dawdle, goggle, and the way Elmer Fudd pronounces grosgrain.
  
• "Voiced" because they involve use of the vocal cords.
• The four sounds that shifted are those in the table below.
  

PIE root	Sound Change	English Derivative	Germanic Cognate (which show the change)	Non-Germanic Cognates (which reflect the PIE)
*bak staff, cane	*b > p	peg	Du pegge	Gk βακτρον (> E bacteria)
*dekm ten	*d > t	ten	Du tien	L decem (> E decemvir, decimate)
		seat		L sedes (>E sedentary)
		sweet		L suade- (>E dissuade, persuade, suasive)
		tame		L domus (> E domestic)
*gel cold	*g > k	cold	Du koud, G kalt	L gelu (> E gelid)
*gwei live	*gw > kw	quick	Du kwiek	Gk βίος, L vivus (> E vivid)
*gwou cow		cow	Du koe, Old Frisian kú	Skt gaus, gaum, go (>E cow), L bos (> E Bovine)
*gwen woman		queen		Gk γυνη,

Again, these changes also occurred word-internally.

ONCE THAT CHANGE HAD HAPPENED, THERE WAS A 'VACUUM' LEFT: THERE WERE NO VOICED STOPS--no /b/, /d/, /g/, or /gw/!

NEXT...

3. Voiced aspirated stops became plain voiced stops. That fills the vacuum.
   
• English does not seem to have voiced aspirated stops of this sort currently.
• "Aspirated" because they involve significant expulsion of air (another way to say it is that they combine the plain voiced stop with an /h/).
  

PIE root	Sound Change	English Derivative	Germanic Cognate (which show the change)	Non-Germanic Cognates (which reflect the PIE)
*bha	*bh > b	beacon, beckon	mDu boenen "scour, scrub"	Gk φῶς (> E phosphorus)
*bhrater		brother	G bruder, Du broeder	Gk φρατήρ (> English phratry), L frater (> E fraternal)
*bhreu		brew	OHG briuwan, ON bruggin	Gk φρεαρ (> E phreatic), L fervere (> E fervent)
*dheu	*dh > d	dead	ON dauthr, Gothic dauths, G tot
*dhwer		door	OHG tor, ON dyrr, Gothic daur	Gk θύρα, L fores
*ghans goose	*gh > g	goose gander	Frisian goes, G gans, Du gans	L anser (>E anserine, merg-anser), Gk χήν (>E chen-o-pod)
*gwhibh	*gwh > gw	wife	Frisian wif, G weib

Again, the changes occurred word-internally as well.

And nowadays there are no voiced aspirated stops left in English.