This change occurred before rhotacization, as original word-final was not lost. But it must have occurred after the Northwest Germanic split, since word-final was not eliminated in Old Norse, instead merging with . was not lost in single-syllable words in southern and central German. Compare PG > OS mi, OE me vs. OHG mir. The OE nominative plural (ME ), OS nominative plural may be from original accusative plural , due to the Ingvaeonic Nasal-Spirant law, rather than original nominative plural , which would be expected to become *-a (OHG -a, compare ON ). Rhotacization: > . This change also affected Proto-Norse, but only much later. and were still distinct in the Danish and Swedish dialect of Old Norse, as is testified by distinct runes. ( is normally assumed to be a rhotic fricative in this language, but there is no actual evidence of this.) PG > Goth ; OE dēor > ModE deer West Germanic gemination: single consonants followed by except became double (geminate). This only affected consonants preceded by a short vowel, because those preceded by a long vowel or by another consonant were never followed by due to Sievers' law. PG > OE biddan, habban > ModE bid, have Ingvaeonic and Anglo-Frisian period This period is estimated to have lasted only a century or so, the 4th to 5th; the time during which the Franks started to spread south into Gaul (France) and the various coastal people began colonising Britain. Changes in this period affected the Ingvaeonic languages, but not the more southerly Central and Upper German languages. The Ingvaeonic group was probably never homogeneous, but was divided further into Old Saxon and Anglo-Frisian. Old Frankish (and later Old Dutch) was not in the core group, but was affected by the spread of several areal changes from the Ingvaeonic area. The Anglo-Frisian languages shared several unique changes that were not found in the other West Germanic languages. The migration to Britain caused a further split into early Old English and early Old Frisian. Ingvaeonic nasal spirant law: Loss of nasals before fricatives, with nasalization and compensatory lengthening of the preceding vowel. Hence PG became ModG Mund but in Ingvaeonic dialects first became . Old English then denasalised the vowels, giving OE > ModE "mouth". Following this > . PrePG * > PG > > > OE > ModE "tooth". (ModG Zahn < OHG zant.) This also applied