The voiced aspirated stops may have first become voiced fricatives before hardening to the voiced unaspirated stops "b", "d", and "g" under certain conditions, however some linguists dispute this. See Proto-Germanic phonology.
Further changes following Grimm's Law, as well as sound changes in other Indo-European languages, can sometimes obscure its effects. The most illustrative examples are used here.
| Change |
Germanic (shifted) examples |
Non-Germanic (unshifted) cognates |
| *p→f |
English: foot,, Dutch: voet, German: Fuß, Gothic: fōtus, Icelandic, Faroese: fótur, Danish: fod, Norwegian, Swedish: fot |
Ancient Greek: πούς (pūs), Latin: pēs, pedis, Sanskrit: pāda, Russian: под (pod), Lithuanian: pėda, Latvian pēda |
| *t→þ [θ] |
English: third, Old High German: thritto, Gothic: þridja, Icelandic: þriðji |
Ancient Greek: τρίτος (tritos), Latin: tertius, Gaelic treas, Irish: trí, Sanskrit: treta, Russian: третий (tretij), Lithuanian: trečias, Latvian trīs |
| *k→h [x] |
English: hound, Dutch: hond, German: Hund, Gothic: hunds, Icelandic, Faroese: hundur, Danish, Norwegian, Swedish: hund |
Ancient Greek: κύων (kýōn), Latin: canis, Gaelic, Irish: cú, Welsh ci |
| *kʷ→hw [xw] |
English: what, Gothic: ƕa ("hwa"), Danish hvad, Icelandic: hvað, Faroese hvat, Norwegian: hva |
Latin: quod, Gaelic: ciod, Irish: cad, Sanskrit: ka-, kiṃ, Russian: ко- (ko-), Lithuanian: ką', Latvian kas |
| *b→p |
English: warp; Swedish: värpa; Dutch: werpen; Icelandic, Faroese: varpa, Gothic wairpan |
Latin: verber |
| *d→t |
English: ten, Dutch: tien, Gothic: taíhun, Icelandic: tíu, Faroese: tíggju, Danish, Norwegian: ti, Swedish: tio |
Latin: decem, Greek: δέκα (déka), Gaelic, Irish: deich, Sanskrit: daśan, Russian: десять (desyat'), Lithuanian: dešimt, Welsh deg, Latvian desmit |
| *g→k |
English: cold, Dutch: koud, German: kalt, Icelandic, Faroese: kaldur, Danish: kold, Norwegian: kald, Swedish: kall, |
Latin: gelū |
| *gʷ→kw |
English: quick, Frisian: quick, queck, Dutch: kwiek, Gothic: qius, Old Norse: kvikr, Danish: kvik, Icelandic, Faroese: kvikur, Swedish: kvick, Norwegian kvikk |
Lithuanian: gyvas |
| *bʰ→b |
English: brother, Dutch: broeder, German: Bruder, Gothic: broþar, Icelandic, Faroese: bróðir, Danish, Swedish, Norwegian: broder |
Sanskrit: bhrātṛ, Russian: брат (brat), Lithuanian: brolis, Old Church Slavonic: братръ (bratr'), Latvian brālis |
| *dʰ→d |
English: door, Frisian: doar, Dutch: deur, Gothic: daúr, Icelandic, Faroese: dyr, Danish, Norwegian: dør, Swedish: dörr |
Irish: doras, Sanskrit: dwār, Russian: дверь (dver'), Lithuanian: durys, Latvian durvis |
| *gʰ→g |
English: goose, Frisian: goes, Dutch: gans, German: Gans, Icelandic: gæs, Faroese: gás, Danish, Norwegian, Swedish: gås |
Russian: гусь (gus') |
| *gʷʰ→gw→w |
English: wife, Proto-Germanic: wiban (from former gwiban), Old Saxon, Old Frisian: wif, Dutch: wijf, Old High German: wib, German: Weib, Old Norse: vif, Icelandic: víf, Faroese: vív, Danish, Swedish, Norwegian: viv |
Tocharian A: kip, B: kwípe (vulva) |
This is strikingly regular. Each phase involves one single change which applies equally to the labials (p, b, bʰ, f) and their equivalent dentals (t, d, dʰ, þ), velars (k, g, gʰ, h) and rounded velars (kʷ, gʷ, gʷʰ, hw). The first phase left the phoneme repertoire of the language without voiceless stops, the second phase filled this gap but created a new one, and so on until the chain had run its course.
| Change |
Germanic examples |
Non-Germanic examples |
| *sp |
English: spew, Gothic: speiwan, Dutch: spuien, German: speien, Danish, Norwegian, Swedish: spy, Icelandic: spýja, Faroese: spýggja |
Latin: spuere |
| *st |
English: stand, Dutch: staan, German: stehen, Icelandic, Faroese: standa, Danish, Swedish: stå |
Latin: stāre, Irish: stad, Sanskrit: sta, Russian: стать (stat'), Lithuanian: stoti |
| *sk |
English: short, Old Norse and Icelandic: skorta, Old High German: scurz |
Lithuanian: skurdus |
| *skʷ |
English: scold, Old Norse: skäld, Icelandic: skáld, Dutch: schelden, Norwegian: skald |
Irish: scioll |
The most recalcitrant set of apparent exceptions to Grimm's Law, which defied linguists for a few decades, eventually received explanation from the Danish linguist Karl Verner (see the article on Verner's law for details).
The Germanic "sound laws", combined with regular changes reconstructed for other Indo-European languages, allow one to define the expected sound correspondences between different branches of the family. For example, Germanic (word-initial) *b- corresponds regularly to Latin *f-, Greek pʰ-, Sanskrit bʰ-, Slavic, Baltic or Celtic b-, etc., while Germanic *f- corresponds to Latin, Greek, Sanskrit, Slavic and Baltic p- and to zero (no initial consonant) in Celtic. The former set goes back to PIE *bʰ- (faithfully reflected in Sanskrit and modified in various ways elsewhere), and the latter set to PIE *p- (shifted in Germanic, lost in Celtic, but preserved in the other groups mentioned here).