Diphthongization of /i:/ and /u:/ was a rather late and parallel rather
than shared change in New High German and early Modern English.  (The
dialects of the Scandinavian-speaking islands in the Baltic also have it
although mainland Scandinavian and Low German don't have it.) There are NHG
dialects where it hasn't happened, unlike English AFAIK. IIANM the change
began earlier but took longer to complete in NHG. In early HG prints */i:/
was spelled _ey_ while */ai/ was spelled _ei_ in order to cater for both
pronunciations. /i:/ had frequently been spelled _y_ in MHG.

As for shared innovations with other Germanic languages English is
unquestionably closest related to Frisian. They share (early)
palatalization of velars in contact with pre-umlaut front vowels, loss of
nasals before fricatives with compensatory lengthening, fronting of *a and
*ā to [& E], unrounding of (the glide of) *au and  monophthongization of
*ai to a new /A:/. Southern Middle English and most of Frisian also share
rounding of the latter. All this clearly identifies Anglofrisian as a
grouping within West Germanic. Parts of Scandinavian has gone through some
similar changes but mostly at a later time and with partly different
conditions, which makes them parallel rather than shared innovations.

As for semantic extension from 'yard' to 'fence', 'farm' and 'village' it's
ubiquitous in Scandinavian. _Tún_ was lost in East Scandinavian and not
extended in West Scandinavian but _gardr_ was extended to 'farm' all over
the place, to 'fence' at least in Swedish and to 'town' in Old Norse. Those
of you who know Old English will enjoy to learn that Constantinople was
Miklagardr in Old Norse. The reflexes of _býr/bœr_, cognate with German
_bauen_ and originally meaning 'farm' means 'village' in Swedish and 'town'
in the other Scandinavian languages. In Latin _villa_ was 'estate' but its
French reflex means 'town'. I think this is well nigh a universal.


Den söndagen den 16:e december 2012 skrev Roger Mills:

> --- On Sun, 12/16/12, Daniel Prohaska <[log in to unmask]<javascript:;>>
> wrote:
> English and Dutch (as well as Frisian and Low German) don't 'do' anything
> differently in this respect, they rather retain a common archaism, the
> Germanic /t/, while the High German varieties are the innovators here and
> shift Gmc /t/ to [s] or [ts]. Any others?
> =======================================
> OTOH, Engl. has at least one of the diphthongizations seen in High German:
> *u: > /aw/-- *hu:s, mu:s, lu:s, Germ haus, maus, laus, Engl. house, mouse,
> louse, vs. Dutch huis, muis, luis (the vowel is /œy/ if I have my IPA
> right.)
> I haven't checked an etymol. dict.
>  of Engl., but I think Germ. zaun 'fence; enclosure', Du. tuin 'garden',
> Engl. town belongs here too. I've found a couple words in Indonesian lgs.
> that have the same semantic range.