About 800, older _hr_ > _r_ in Denmark. Soon after 800, older diphthongs became simplified in Denmark, e.g.,
_au_ > _u_ cp. O. Ic. _þau_, O.Gutnic _þaun_ = O. Dan. _þusi_ pronounced _þøsi_. _ai_, _ei_ > _i_ cp. O. Ic. _stein_, O.N. _stæin_, O.Gtnc. _stain_ = O. Dan. _stin_. _io_, _iau_ > _u_ cp. O.N., O. Ic. _briote_, O.Gtnc. _briauti_ = O. Dan. _biruti_.
Before 1000, _ē_ > _æ_ cp. O.N., O. Ic. _sér_ = O. Dan. _sær_ (written _sar_). About 1,000, appears in O. Sw.--O. Dan. an excrescent _d_ between _nn_ and _r_, e.g., _mantr_, pronounced _mandr_ (see Noreen, p. 526).
Not until the year 1,000, or the beginning of the 11th Century, do dialectal differentiations seem to be fully developed. O.N., which in general preserves best the characteristics of the old Northern speech, undergoes at this time a few changes that differentiate Dan. and Norse still more. O. Sw. remains throughout closer to O. Dan. The two together are therefore called East Scandinavian. Old Icelandic, that is, Norse on Icelandic soil, develops its own forms, remaining, however, in the main very similar to O.N. These two are then called West Scandinavian. The following are some of the chief differences between West and East Scandinavian at the time (from Noreen, P.G.(2)I, 527):
1. _I_--(_R_) and _U_--_Umlaut_ in W.S. Absence of it in E.S., e.g.,
W.S. _hældr_ E.S. _halder_. 3 sg. pres. of _halda_, "to hold." W.S. _i gær_, "yesterday," E.S. _i gar_. W.S. _lǫnd_, pl. "land," E.S. _land_.
2. Development of _i_, _e_, _y_ into a consonantal _i_ in diphthongs in W. S., not so in E. S., e.g.,
W.S. _siá_, "to see," E.S. _sēa_. W.S. _fiánde_, "enemy," E.S. _fiande_. W.S. _biár_, "of a village," E.S. _býar_.
3. Assimilation of _mp_, _nk_, _nt_, respectively, to _pp_, _kk_, _tt_ in W.S., retention of them in E.S., e.g.,
W.S. _kroppen_, "crippled," E.S. _krumpin_. W.S. _ækkia_, "widow," E.S. _ankia_. W.S. _batt_, "bound," E.S. _binda_. pret. of _binda_,
W.S. _sk_, e.g., _kallask_, E.S. _s_, _kallas_.
W.S. _ek_, _vér_ (_mér_), E.S. _iak_, _vīr_, _ér_ (_þer_), _sem_, _īr_, _sum_.
Assimilation of _mp_ to _pp_ and _nk_ to _kk_ appears also quite early in Danish and Swedish, e.g., _kap_ (_kapp_) and _drocken_ (see Kalkar), _kapp_ and _drokken_ (Sw.). _U--Umlaut_ seems to be more limited in O.N. than in O. Ic. O. Ic. _hl_, _hn_, _hr_ initially appear early as simple _l_, _n_, _r_ in O.N. (see Noreen 528), e.g., O. Ic. _hlaupa_, O.N. _loupa_; O. Ic. _hniga_, O.N. _niga_; O. Ic. _hringr_, O.N. _ringr_; O. Ic. _fn_ appears in O.N. as _bn_ or _mn_, e.g., O. Ic. _nafn_, O.N. _namn_ (N. Norse _navn_, _nabn_, _namn_). Initial _hv_, which was a heavy guttural spirant, became _kv_ in Western Norway, _kv_ and _khv_ in Iceland (though written _hv_ still), e.g., O.N., O. Ic. _hvelva_, Norse _kvelva_. O.N. _ø_ became _æ_ in Iceland, _døma_ > _dæma_. O.N. _æi_ became _ei_ in Iceland, e.g., O.N. _stæin_ > O. Ic. _stein_, O.N. _bæin_ > O. Ic. _bein_ (_stin_ and _bin_ in O. Dan.).