The official alternative: the h-sistemo

The absence of Esperanto's letters on typewriters meant that Ludoviko Zamenhof soon after publishing the language needed to suggest an alternative system. He made his proposal in the Aldono al la Dua Libro in 1888, which was incorporated into the Fundamento. This system is called the h-metodo because it involves using the letter h to indicate that the preceding letter should have an accent on it, with the exception of u:

ch = ĉ, gh = ĝ, hh = ĥ, jh = ĵ, sh = ŝ, u = ŭ

Since the h-sistemo exists in the Fundamento it is an offical part of the language, accepted as such by the Akademio de Esperanto. Opponents of the system point out that there is scope for confusion in words where the letter h would naturally follow one of the trigger letters, such as in flughaveno (airport).