"step-" (Epinal Glossary 726, 1070); but in other branches of West Germanic eventually became unless followed by , e.g. Old Saxon breost "breast" vs. treuwa "fidelity". In most variants of Old Norse, > > or , without regard to a-mutation, e.g. Old Icelandic djúpr. Effects of a single nasal consonant Old English derives from a type of Germanic in which single had the same effect on preceding and as a nasal stop followed by another consonant. The effect occurs in other West Germanic languages, though more erratically, and sometimes in Old Norse. Old Norse nema, Old High German neman : Old Frisian nima, nema, Old Saxon niman, neman : Old English niman "to take" Old High German gi-noman, Old Frisian nomen : Old Norse numinn, Old English numen, Old Saxon numan "taken" (past participle) Old High German gomo "man", Old Frisian gomo : Old Norse gumi, Old English guma, Old Saxon gumo a-mutation was also sometimes blocked before single , again with much variation among languages. Old Saxon honig, -eg, Old High German : Old English (for older -æg), Old Frisian hunig, Old Norse hunang Alternative ideas A number of scholars have questioned the traditional model of Proto-Germanic a-mutation in whole or in part. In particular, the rare a-mutation of to "as a P[roto]-G[ermanic] phenomenon has always been contested." Lloyd, for example, proposed an alternative explanation for all apparent instances of a-mutation of ; he suggested that "the partial overlapping in Germanic of the two phonemes (represented in all environments by ) and (with the allophones and ) led to the occasional development of an e-allophone of i by systemic analogy". Cercignani, on the other hand, argued that "no 'umlaut' phenomena can be assumed for Proto-Germanic", preferring to ascribe these changes to "the prehistory of the individual languages." Notes References Campbell, A. (1959). Old English Grammar. Oxford University Press. . Cercignani, Fausto (1980). "Early 'umlaut' phenomena in the Germanic languages", Language 56:1, pp. 126–136. Collitz, Hermann (1918), "Early Germanic vocalism", Modern Language Notes 33:6, pp. 321–333. Gordon, E. V. (1957). An Introduction to Old Norse. Second Edition revised by A. R. Taylor. Oxford University Press. . Grønvik, Ottar (1983). Die dialektgeographische Stellung des Krimgotischen und die krimgotische cantilena. Oslo, Universitetsforlaget. Kock, Axel (1898). "Der a-umlaut und der Wechsel der endvocale a: i(e) in den altnordischen sprachen", Beiträge zur Geschichte der deutschen Sprache und Literatur 23, pp. 484–554. Kock, Axel (1890).