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 well, and was best considered an allophone of , occurring only after a nasal or when geminated. But after became word-initially in Old English, it makes sense to consider the stop the basic form and the fricative the allophone. The evidence for the allophone after front vowels is indirect, as it is not indicated in the orthography. Nevertheless, the fact that there was historically a fronting of to and of to after front vowels makes it very likely. Moreover, in late Middle English, sometimes became (e.g. "tough", "cough"), but only after back vowels, never after front vowels. This is explained