Unproductive affixes: eN- and -en

I will finish the review of the structural properties of overtly marked verb-deriving processes in English by briefly looking at the attested neologisms involving the affixes eN- and -en. Derivatives with these affixes are extremely rare, which warrants the conclusion that they are analogical formations and are not derived on the basis of a productive rule. Nevertheless, these forms share some interesting properties.

Derivatives with the prefix eN- seem to have a locative interpretation (encode, endistance, envision, emplane, embus), although an ornative meaning is also once attested (enhat), as well as a causative one (embrittle). Thus eN-, if used at all to create a new word, appears to be more or less reserved for the spatial meanings, which is in line with the analysis of en- as a spatial (prefixed) preposition, as proposed by Walinska de Hackbeil (1985).¹

The suffix -en is attested with only two causative derivatives (crispen, outen), which notably also have earlier zero-derived equivalents. As previously mentioned, there is a phonological restriction on -en derivatives that the suffix may only be preceded by monosyllabic bases ending in one obstruent (optionally preceded by a sonorant). The two isolated neologisms in the OED at least partially conform to this restriction in that both bases end in an obstruent and are monosyllabic (crispen, outen).

¹ Note that Walinska de Hackbeil's analysis also involves a zero-suffix as the head of the word, an analysis whose value seems questionable to me.