Helbrecht Paper: Terminology 'modal prefix'

[Koontz John E]

Lipkind (1945:17) refers to the Winnebago prefix wa- 'which probably means
'something' or 'thing' ... [and] is used to make transitive verbs
intransitive and to form nouns out of active and stative verbs' as the
'modal prefix'.  Johannes says 'this is definitely a misnomer', and I'd
certainly agree if I thought Lipkind had anything like the contemporary
sense of modal in mind.  This prefix definitely has nothing to do with
concepts like ability, possibility, obligation and the like.  However,
I've always assumed that Lipkind had in mind here either an old usage of
modal or some idiosyncratic usage of his own, in which modal was an
adjective meaning 'having to do with modes' and distinctions like
transitive vs. intransitive or verb vs. noun (and perhas also indicative
vs. subjunctive) were conceived of as different modes of signification.
Does anyone know of such a usage?

JEK