The major period of literary activity in Manx took place during the second half of the eighteenth century and thus belongs to Volume 4 of the New History. This may be regarded as the ‘classical’ period of the language, and is also the period in which the first descriptions of it in grammar and lexicography were written, though the first published dictionary appeared in 1835.

Already under threat from the pressure of English, the language was still widely spoken in the first half of the nineteenth century, appearing in newspaper advertisements and articles, in use in the courts and in the churches (there were editions of the Book of Common Prayer in 1840 and 1842, and a collection of hymns in 1830 and 1846). Publication tailed off and nothing of great importance appeared; church services in Manx Gaelic became fewer, down to once a month or even once a quarter by 1875 (and an increasing proportion of the Anglican clergy come from off the Island). Although 1848 there were some sixty Wesleyan Methodist local preachers who preached only in Manx, it seems that Cregeen's expectation in the preface to his dictionary dated 1834, that the book would be ‘an important acquisition’ to ‘the students of Divinity and the students of Law’ for whom the language was ‘so essentially necessary within the precincts of Mona’, was not to be fulfilled, true as it may have been earlier in his own lifetime. His dictionary was the only one to be published as a commercial venture (apart from the abortive attempt of Kelly's Triglott, which in any case was aimed at a different public); Kelly's own Manx dictionary appeared only in edited form in the series of The Manx Society for Publication of National Documents, vol. XIII in 1866, a series which, apart from the dictionary, Kelly's Grammar, the abridgment of Paradise Lost and some short pieces in its Miscellany volumes, contains nothing else in Manx until the very end (see below). Cregeen's ‘Introduction’ defended his enterprise: ‘Some will be disposed to deride the endeavour to restore vigour to a decaying language … But those will think otherwise who consider that there are thousands of natives of the Island that can at present receive no useful knowledge whatever, except through the medium of the Manks language.’