Sound Change

Historical Linguistics and Language Families

Course 1 · Chapter 2 · Sound Change

Chapter 1 listed the kinds of language change. Sound change is the kind with the strongest claim to being regular, which is why it is the foundation of everything else in this course. This chapter names the types, sets out what "regular" means, and then works through the most famous sound change in the field.

The idea in a box

A sound change is a change in a language's pronunciation. It may replace one sound with another (phonetic change) or alter the sound system more broadly, for example by merging two sounds (phonological change). Because it is regular, we can use it to prove relationships between languages.

The Types of Sound Change

Wikipedia's article on sound change lists these types, and every one connects to something from Phonetics and the IPA.

Type	What happens	Example from the source
Assimilation	one sound becomes more like a neighbour	Latin kom- becomes con- before t, d or n (contactus, condere)
Dissimilation	one sound becomes less like another	Old Spanish omne to hombre
Lenition	a consonant weakens, e.g. a stop becomes a fricative	Italian intervocalic b to v: caballum to cavallo
Fortition	a consonant strengthens (the opposite of lenition)	(none given)
Deletion	a sound is lost; aphaeresis (initial), syncope (medial), apocope (final)	Old French estat to état (syncope); opossum to possum (elision)
Haplology	a syllable next to a similar one is removed	Old English Englaland to England
Epenthesis	a sound is inserted	Latin humilis to English humble
Prothesis	a sound is added at the start of a word	Latin status to Spanish estado
Metathesis	two sounds switch places	Old English thridda to Middle English third
Merger	two sounds become one (a phonological change)	(none given)

The article also notes nasalisation: French words ending in -in now have the nasal vowel [ɛ̃]. It does not define "split" as a separate type, so this course does not either.

Watch out: lenition is not one fixed list

The source defines lenition simply as a consonant weakening, with a stop becoming a fricative as one example. Do not read that as a rule that all weakening goes in a fixed direction; judge each case from the sounds themselves (Phonetics and the IPA 3 gives you the manner scale).

Conditioned and Unconditioned Change

An unconditioned change applies in all environments. A conditioned change applies only in certain contexts, and linguists write it as A > B / X __ Y: A becomes B between X and Y. The source's example is the Italian change of intervocalic b to v, with V__V standing for "between vowels". Sandhi, the sound change at word boundaries, is conditioned change too (Phonetics and the IPA 8 showed several cases).

// A > B / X __ Y   ("A becomes B between X and Y")
b > v / V __ V      Italian: caballum > cavallo

The Neogrammarian Idea: Regularity

The Neogrammarians treated sound change as regular and exceptionless, expressed as sound laws (the source names Grimm's law and Grassmann's law). Wikipedia lists four heuristics: sound change has no memory, ignores grammar, is exceptionless, and is inevitable. It treats these as guidelines, not inviolable rules.

Apparent exceptions can come from analogy, dialect borrowing or other causes.
Lexical diffusion challenges exceptionlessness: a change may spread word by word, though it often eventually reaches the whole lexicon. Changes that affect only a few words are called sporadic.
Each change is limited in space and time.

Grimm's Law

Grimm's law (also called the First Germanic Consonant Shift) is a set of sound laws describing how Proto-Indo-European (PIE) stop consonants developed in Proto-Germanic during the first millennium BCE. The reconstructed forms are marked with an asterisk; the dedicated discussion of the asterisk comes in Chapter 4.

Wikipedia describes it as a chain shift with three phases, applied in the order 3, 2, 1:

Phase	PIE	Proto-Germanic	Changes
1	voiceless stops	voiceless fricatives	p > f, t > þ, k > h, kʷ > hw
2	voiced stops	voiceless stops	b > p, d > t, g > k, gʷ > kʷ
3	voiced aspirated stops	voiced stops or fricatives	bʰ > b, dʰ > d, gʰ > g, gʷʰ > gʷ

The letter þ ("thorn") is the Old English and Germanic letter for the th sound; reading it as [θ] is my gloss, not the page's. The order matters because the sounds move into places that were just vacated: voiced stops become voiceless stops only after the old voiceless stops have already left to become fricatives.

Examples from the page

PIE	Meaning	Latin	English
*pṓds	foot	pēs, pedis	foot
*tréyes	three	trēs	three
*ḱwón-	dog	canis	hound
*déḱm̥t	ten	decem	ten

Latin did not undergo Grimm's law, so it keeps the old sounds; English did, so it shows the new ones. Compare the first consonants: Latin p against English f (pedis and foot), Latin t against English th (trēs and three), Latin c [k] against English h (canis and hound), and Latin d against English t (decem and ten).

The people behind it

Friedrich von Schlegel noted the Latin p / Germanic f correspondence in 1806.
Rasmus Rask extended it to Sanskrit, Greek and the full range of consonants in 1818.
Jacob Grimm stated the rule in Deutsche Grammatik in 1822 and extended it to standard German. He noticed exceptions that his law did not predict.
Karl Verner, a Danish linguist, explained those exceptions with Verner's law, which voiced certain Germanic voiceless fricatives under specific conditions.

Verner's law is a good example of the regularity principle at work. The exceptions to a sound law were not accepted as random; they were assumed to have a cause, and the cause was found.

Note on sources

The sound-change types, the conditioned/unconditioned distinction, the regularity heuristics, the three phases of Grimm's law, the four examples and the history come from Wikipedia's articles on sound change and Grimm's law. The page's English father example (PIE *ph₂tḗr to Proto-Germanic *fadēr) is left out because its d needs Verner's law, which this chapter only mentions. The Latin pater and cornu pairs I might have used are not on the page and are left out. The [θ] reading of þ and the "vacated places" remark are mine.

Try It Yourself

Exercise 1

For each pair, name the Grimm's law phase and the sound change: pedis / foot, trēs / three, canis / hound, decem / ten.

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Exercise 2

Name the type of sound change in each: Latin kom- to con-; Old English thridda to third; Latin humilis to humble; Old English Englaland to England; Latin status to Spanish estado.

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Exercise 3

Write the Italian change caballum to cavallo as a conditioned rule. Then explain how Verner's explanation of Grimm's exceptions supports the Neogrammarian idea.

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Chapter 2 Quick Reference

Types: assimilation, dissimilation, lenition, fortition, deletion, haplology, epenthesis, prothesis, metathesis, merger
Conditioned change is written A > B / X __ Y; unconditioned applies everywhere
Neogrammarians: sound change is regular; exceptions have causes (analogy, borrowing, others); lexical diffusion is the challenge
Grimm's law: voiceless stops > fricatives, voiced stops > voiceless stops, voiced aspirates > voiced stops or fricatives
Verner's law explained Grimm's exceptions

Coming next

Historical Linguistics and Language Families 3 turns regular sound correspondences into proof of relationship: the comparative method.