a witty remark
In this context, "jest" refers to something done or said in a playful or joking manner, implying that the writings were not meant to be taken seriously. The older brother suggests that the inscriptions might have been created as a joke or for amusement, rather than conveying a serious message.
Vernacular writings are written in the native language of the place where they are composed.
The gerund (verbal noun), writing does have a use for the plural form 'writings'. The term 'Writings' or 'The Writings' (note the capitalization) is a modern term for Hagiographa, the third of the three divisions of the Hebrew Scriptures, composed of Psalms, Proverbs, Job, Song of Solomon, Ruth, Lamentations, Ecclesiastes, Esther, Daniel, Ezra, Nehemiah, and Chronicles. I could find only one dictionary (oxforddictionaries.com) that also gave the definition as a word for books, stories, or other written works.
'Ingredion' as written is gibberish.
The definition of an epistolary novel is: a novel written in the form of a series of letters.
In this context, "jest" refers to something done or said in a playful or joking manner, implying that the writings were not meant to be taken seriously. The older brother suggests that the inscriptions might have been created as a joke or for amusement, rather than conveying a serious message.
Georges Michel Sarotte has written: 'Like a brother, like a lover' -- subject(s): American literature, Gay men, Gay men in literature, Gay men's writings, American, History and criticism, Homosexuality and literature, Intellectual life, Gays' writings, American
Vernacular writings are written in the native language of the place where they are composed.
Jennifer Hennings has written: 'The penny doll' -- subject(s): Children's writings, Children's writings, American, Dolls, Fiction
Richard Wever has written: 'The dramatic writings'
Genesis, written by Moses.
Jeremiah Evans has written: 'The story of I-Am-A-Dragon' -- subject(s): Children's writings, American, Mothers and sons, Fiction, Children's writings
Pertaining to the sibyls; uttered, written, or composed by sibyls; like the productions of sibyls.
Brother Mandus has written: 'The Divine Awakening'
Grace Norton has written: 'The early writings of Montaigne'
Patrick has written: 'The writings of Bishop Patrick, 1074-1084'
Michael. Fordham has written: 'The self in Jung's writings'