That this comes under zero morpheme may explain why Bender (2000) states that many scholars view affixation as the only process, adding that they see other morphological processes as forms of affixation.
It takes the existence of zero morphemes as implicit transposition takes place.
Old English Deverbal Substantives Derived by Means of a Zero Morpheme
Kastovsky, Dieter 1968: Old English Deverbal Substantives Derived by means of a Zero Morpheme
Then, they embed this under [[+ or -] cause] small v's, but initially assume that [[+ or -] cause] small v's are always a zero morpheme, as in English.
We suggested that the "mistakes" made at this stage were due to children's assumption that Japanese is exactly like English, that is, that [[+ or -]cause] v's are zero morphemes.
These derivatives have to be regarded as syntagmas, too, and since they stand in a formal-semantic opposition to parallel explicit syntagmas with overt suffixes, they have to be analysed not just as conversions or functional shifts from one word-class to another, but as derivatives containing a zero morpheme
instead of an overt derivational suffix (10) cf.
Condition (e), for the zero morpheme
, says: SitT= RT; the entity e belongs to the class of state or event entities E or S, and SitT ([t.
either word order or agreement); (6) the presence or absence of a zero morpheme
and whether nouns and verbs exist as bare roots or must necessarily be inflected; (7) whether, when inflections are omitted, the remaining form is pronounceable or not; and (8) whether the form is memorized or derivable by rule, that is, whether it is regular or irregular.
This claim is arguable because zero morpheme
is generally considered to be an affix, that is, a form-meaning complex (see, for example, Marchand's  or Kastovsky's [1968, 1969, 1982] theories of zero derivation, or Haas's  discussion of zero in linguistics), the meaning of which corresponds to that of the respective overt affix.
Kastovsky 1978: 232) have acknowledged that they cannot explain the existence of zero morphemes
or zero derivation.