While only an erstwhile linguist and philologist, vernacular in my parlance comes in the form of the logically extended use of the term when applied as an adjective to architecture and the decorative arts. I am reminded of a lecture I had given a year or so ago about 18th century English furniture and the first question I fielded was on why it was that English furniture looked the way it did, and French furniture, produced just a few miles away, looked so markedly different. Surprising that this question, that could only be considered suitably in a tome of a half-million words, with an equivalent number of images, was asked by the curator of a well-known local collection. Perhaps she was trying to catch me out, but her tone suggested that she really wanted to know. I dodged the bullet, as it were, answering that this was a question with no simple answer, but did suggest one aspect might be the woods available to English makers, with the corner on the mahogany market yielding pieces with a liberal use of carving and an iridescent sheen that French makers could not accomplish with the local woods and the comparative paucity of exotic woods necessitating their sparing use in the form of veneers.
Of course, this provides a little bit of an introduction, albeit with a deterministic bent, into the development of vernacular style. The consideration of any particular vernacular is never so simple as Abbé Laugier seemed to think, with, in his view, classical architecture mimicking archaic Greek trabeated structures. Moreover, style is hardly static, so any consideration of any vernacular style anywhere is always an exercise in trying to hit a moving target.
Keith and I recently returned from a trip to our adopted home of Honolulu, a city we love for a variety of reasons, but one of them is its built environment. The main original commercial core of Honolulu with its mauka axes of Nuuanu, Bethel, Fort, and Bishop Streets, running Diamond Head direction from their makai terminus of Merchant Street contains a welter of 19th and early 20th century buildings that, despite an overarching and predominantly European style, are nevertheless possessed to varying degrees of a local vernacular.
A particular favorite of ours is the marvel of fanciful decoration and architectural restatement that is the Alexander & Baldwin Building at 822 Bishop Street, built in 1929 and designed by Honolulu architects Charles William Hickey and Hart Wood. 
Their classical training doubtless contributes to an exterior design that, at first glance, bears a striking resemblance to a Florentine palazzo, with its massively scaled ground floor hinting at what would have been rusticated if built in an earlier day, and then gradually lightening visually, to a loggiaed top storey with an overhanging eave and fronted by a balustrade. Italianate in outline, but stylistic motifs that would have vernacular resonance are uniformly substituted for classical ones. In the detail image, for instance, where one might reasonably expect the use of bukrania in the frieze decoration, the architects used the heads of water buffaloes. 
Although now largely forgotten, Hawaii agriculture in the 19th and early 20th centuries was dependent on the labor of these beasts, and doubtless, with so much of Alexander & Baldwin’s fortunes derived from the production of sugar and other agricultural products- most notably rice, still an agricultural staple in Hawaii at the time this building was constructed- this sort of apostrophe was considered appropriate. The building is replete with orientalia, with the post and lintel construction of an entranceway, for example, of Italian travertine, but liberally embellished with Chinese fretwork.