Editing Grimm's law (section)

==Further changes==

Once the sounds described by Grimm's law had changed, only one type of voiced consonant was left, with no distinction between voiced stops and voiced fricatives. They eventually became stops at the start of a word (for the most part), as well as after a nasal consonant, but fricatives elsewhere. Whether they were plosives or fricatives at first is therefore not clear. The voiced aspirated stops may have first become voiced fricatives, before becoming stops under certain conditions. But they may also have become stops at first, then become fricatives in most positions later.

Around the same time as the Grimm's law sounds shifted, another change occurred known as [[Verner's law]]. Verner's law caused the voiceless fricatives that resulted from the Grimm's law changes to become voiced under certain conditions, creating apparent exceptions to the rule. For example:

* Proto-Indo-European ''*bʰréh₂tēr'' ("brother") > Proto-Germanic ''*brōþēr'' (Old English ''broþor'', Old High German ''bruothar''/''bruodar'')
* Proto-Indo-European ''*ph₂tḗr'' ("father") > Proto-Germanic ''*faðēr'' (Old English ''fæder'', Old High German ''fatar'')

Here, the same sound ''*t'' appears as ''*þ'' {{IPA|/θ/}} in one word (following Grimm's law), but as ''*d'' {{IPA|/ð/}} in another (apparently violating Grimm's law). See the [[Verner's law]] article for a more detailed explanation of this discrepancy.

The early Germanic ''*gw'' that had arisen from Proto-Indo-European {{PIE|''*gʷʰ''}} (and from {{IPA|''*kʷ''}} through Verner's law) further changed with various sorts:

* After ''*n'' it was preserved as a labiovelar stop ''*gw'', but later changed to a plain velar ''*g'' in [[West Germanic languages|West Germanic]].
* Following vowels, it seems to have become ''*w'', presumably through a fricative stage ''*ɣʷ''.
* Word-initially, the most plausible reflex is labiovelar stop ''*gʷ'' at first, but the further development is unclear. In that position, it became either ''*w'', ''*g'' or ''*b'' during late Proto-Germanic.
* The regular reflex next to ''*u'' would likely have been ''*g'', due to the labial element before a labial vowel being lost in Proto-Indo-European, which continued to act as a [[surface filter]]. (See [[boukólos rule]])

Perhaps the usual reflex was ''*b'' (as suggested by the connection of ''bid'' < ''*bidjaną'' and Old Irish ''guidid''), but ''*w'' appears in certain cases (possibly through dissimilation when another labial consonant followed?) like ''warm'' and ''wife'' (provided that the proposed explanations are correct). Proto-Germanic ''*hw'' voiced by Verner's law fell together with this sound and developed identically, compare the words for 'she-wolf': from Middle High German ''wülbe''{{citation needed|date=October 2014}} and Old Norse ''ylgr'', one can reconstruct Proto-Germanic nominative singular ''*wulbī'', genitive singular ''*wulgijōz'', from earlier ''*wulgwī'', ''*wulgwijōz''.<ref>{{cite journal | title = Gothic 'bagms' and Old Icelandic 'ylgr' | journal =  NOWELE | year = 1995 | first = F. B. J. | last = Kuiper | author-link = F. B. J. Kuiper | volume = 25 | issue = 1| pages = 63–88 |doi=10.1075/nowele.25.04kui}}</ref>{{failed verification|date=October 2014}}