Mark Twain passage of boat, was a measure on the sounding line. Twain is an archaic term for "two", as in "The veil of the temple was rent in twain." The riverboatman's cry was "mark twain" or, more fully, "by the mark twain", meaning "according to the mark [on the line], [the depth is] two [fathoms]", that is, "The water is deep and it is safe to pass." Twain said that his famous pen name was not entirely his invention. In "Life on the Mississippi", he wrote: Captain Isaiah Sellers was not of literary turn or capacity, but he used to jot
Old English phonology fronting of the open vowel to in certain cases. It also underwent vowel shifts that were not shared with Frisian: smoothing, diphthong height harmonization, and breaking. Diphthong height harmonization and breaking resulted in the unique Old English diphthongs , , , . Palatalization yielded some Modern English word-pairs in which one word has a velar and the other has a palatal or postalveolar. Some of these were inherited from Old English ("drink" and "drench", "day" and "dawn"), while others have an unpalatalized form loaned from Old Norse ( and ). Old English had four major dialect groups: Kentish, West Saxon,