Semantics of beginning of the verbs with the root -čа-/čьn- in the history of Russian and the problem of complex future tense grammaticalization

The paper deals with specific semantics, in the diachronic perspective, of verbs with
the root -čа-/čьn- (načati / počati / učati), which, when combined with an infinitive, have
been considered as grammaticalized auxiliaries of the complex future tense. The original
semantics of these verbs was different from the meaning of the modern Russian verb
načatʼ because they denoted not the initial phase of a situation, but the onset of the situation
as a whole. This semantic specificity, presented in Old Church Slavonic, Old Russian
and Middle Russian texts up to the New Age, explains all peculiarities of the usage
and compatibility of these verbs and accounts for the illusion that they function as
grammaticalized forms. The verbs in question display these properties both in the present
and in the past tense, their frequency in either of the tenses being determined by the narrative
/ non-narrative nature of the text.
The verb učatʼ, which first appeared in Middle Russian, was widely used throughout
that period, and then lost popularity just as quickly, is no different in meaning than
načatʼ / počatʼ. Its high frequency in the presence tense with reference to the future was
largely connected with its use in Moscow notarial formulae; in provincial official documents
it is not so dominant, and in narrative texts, even within the official level of discourse,
the use of učatʼ in the past tense prevails. None of these verbs were grammaticalized
into future auxiliaries; their differences from modern Russian načatʼ are stipulated
by the specifics of their semantics, which becomes phasal proper in the dialect system of
the Center only in modern time.