There are two conventional sets ASCII substitutions for the letters in the Esperanto alphabet that have diacritics, as well as a number of graphic work-arounds.
However, since the Esperanto letters with diacritics do not appear on standard computer keyboard layouts (French computer keyboards, unlike manual typewriters, typically assign the circumflex only to letters that bear it in French orthography), various alternative methods have been devised for inputting them or substituting them in type.
The original method, suggested by Zamenhof for people who did not have access to a French typewriter, was a set of digraphs in h, now known as the "Zamenhof-system" or "h-system".
Where proper orthography has sh, the letters should be separated with an apostrophe or a hyphen, as in ses-hora (six-hour) or flug'haveno (airport).
"[7] This provision covers situations such as using the x-system as a technical solution (to store data in plain ASCII) yet still displaying proper Unicode characters to the end user.
One common solution, such as the one used in Wikipedia's MediaWiki software, is to use xx to escape the ux to ŭ conversion, e.g. "auxx" produces "aux".
[10] There are several ad hoc workarounds used in email or on the internet, where the proper letters are often not supported, as seen also in non-ASCII orthographies such as German.