ASCII and Unicode quotation marksby Markus KuhnSummary: Please do not use the ASCII grave accent (0x60) as a left quotation mark together with the ASCII apostrophe (0x27) as the corresponding right quotation mark (as in `quote' ). The two ASCII characters0x22 QUOTATION MARK 0x27 APOSTROPHEare supposed to represent the neutral (vertical) glyphs commonly used on typewriters. In ASCII it is used to represent a punctuation mark (such as right single quotation mark, left single quotation mark, apostrophe punctuation, vertical line, or prime) or a modifier letter (such as apostrophe modifier or acute accent.) TeXThe font cmtt10 in TeX’s Computer Modern family follows the example of the PostScript standard encoding by providing a straight double quotation mark and directional single quotation marks on the ASCII positions 0x22, 0x60, and 0x27. It also provides a straight single quotation mark, grave accent, and acute accent on code positions 0x0d, 0x12, and 0x13, respectively, but it lacks directional double quotation marks:U+0022 QUOTATION MARK " U+0027 APOSTROPHE \char"0D U+0060 GRAVE ACCENT \char"12 U+00B4 ACUTE ACCENT \char"13 U+2018 LEFT SINGLE QUOTATION MARK ` U+2019 RIGHT SINGLE QUOTATION MARK 'Therefore, to demonstrate the result of abusing ASCII’s straight quotation mark and graph accent as directional quotation marks in a document written in LaTeX, you can write \texttt{\char"12 quote\char"0D} .