Uncle Jazzbeau’s Gallimaufrey

the house is building 2

Thanks to reader ACW for pointing me at a discussion of the progressive passive in the OED. The entry for be, III.15:

15. With the present participle, forming continuous varieties of the tenses. a. With active signification. In OE only wæs was so used, forming a kind of imperfect; the present was in use by the 13th c. In later times this was confused iwth a formation upon the vbl. sb. of which see examples under A prep.1 13. The OE he wæs feohtende, and ME ‘he was a-fighting’ meet in the modern ‘he was fighting.’

b. With passive signification: in such expressions as ‘the ark was building,’ the last word was originally the gerund or verbal substantive, and the full expression was ‘the ark was a-building or in building’ of which see instances under prep.1 13.

c. The ambiguity of the construction ‘is building’ in the two preceding senses has led in modern Eng. to the use in the latter sense of ‘is being built,’ formed upon the present pple. passive ‘being built.’

Otto Jespersen also discusses this in A Modern English Grammar, volume V:

9.2.2. Like other nexus-substantives gerunds were originally indifferent to the distinction between active and passive meaning; accordingly in some contexts they are still understood passively. [...]

9.2.3. A passive sense is particularly frequent after the verbs need, want, require, deserve, bear, which are combined with an infinitive in the active sense [...] Di M 480 That needs no accounting for [...]

To avoid ambiguity, however, a new passive gerund developed from about 1600, and now we distinguish “they are fond of teasing” and “they are not fond of being teased” [...] Sid. Arc. 1.11 for fear of being mistaken [...]

9.2.6. This passive is now of everyday usage.

So, those Victorian grammarians had it wrong. The progressive passive hits literary English during Elizabethan times. As for the preposition a: “Action: with a verbal sb. taken actively. With be: engaged in. arch. or dial. In literary Eng. the a is omitted, and the verbal sb. treated as a particple agreeing with the subject, and governing its case, to be fishing, fighting, making anything. But most of the southern dialects, and the vulgar speech both in England and America retain the earlier usage.”