Johano, John or Ĝon? Three ways to write a name

A name in Esperanto can be written three ways, and the Akademio de Esperanto accepts all three. Fully Esperantised with an -o, respelt in Esperanto letters with no ending, or left exactly as its owner writes it.

These are the Akademio's own examples, from its 2013 recommendation.

• Mi loĝis en Nov-Jorko. - I lived in New York.
• Mi legas libron de Kalocsay. - I am reading a book by Kalocsay.

What Zamenhof did

The people in the Fundamento's Ekzercaro all have Esperanto names ending in -o:

• Johano kaj Petro estas amikoj. - Johano and Petro are friends.

Women's names take -o too. In the Fundamento, Mary is Mario. Today you also meet Maria, Sofia and Berta. PMEG says the Fundamento's -o is the model, but -a women's names are very widespread and must be tolerated; an -a is entirely fine when the national form already ends in -a, because the name then counts as not Esperantised. For Mary it lists three options:

Zamenhof stopped halfway with surnames. In §12 George Washington is Georgo Vaŝington: the given name Esperantised, the surname respelt with no ending. He wrote his own name the same way, Zamenhof, with no -o.

Three systems, and no single rule

The Akademio's Rekomendo de la Akademio pri la uzo de propraj nomoj (Oficiala Informo 22, 10 October 2013) replaced its 1989 recommendations. It names the three systems, and then declines to choose:

...nun ne eblas rekomendi unu solan ĉiam uzindan manieron trakti diversajn proprajn nomojn en Esperanto.

...it is not possible now to recommend one single method, always to be used, for treating different proper names in Esperanto.

• Akademio de Esperanto, 2013

It does lean one way, with modern examples: Vindozo (Windows), Linukso (Linux), Guglo (Google).

Indas plu flegi kaj subteni la kutimon plene esperantigi ofte uzatajn proprajn nomojn.

It is worth continuing to cultivate and support the habit of fully Esperantising frequently used proper names.

• Akademio de Esperanto, 2013

And it settles the question learners ask first:

Ĉiu esperantisto povas mem decidi kiuforme uzi sian nomon en la Esperanta medio.

Every Esperantist may decide for themselves in what form to use their name in an Esperanto setting.

• Akademio de Esperanto, 2013

A footnote on Zamenhof and Vaŝington. The 1974 Eighth Official Addition had read these two Fundamento spellings as full names with the ending silently dropped. In 2013 the Akademio annulled that reading: they are simply partly Esperantised.

Who gets which

Usage leans by who the person is:

• Mia nomo estas Mikaelo. - My name is Mikaelo.

Often only the given name is Esperantised and the surname kept: PMEG's example is Christeno Pedersen.

Esperanto has no compulsory rules for capitals (PMEG: Pri majuskloj kaj minuskloj ne ekzistas devigaj reguloj en Esperanto), so a surname printed in capitals, as in Kálmán KALOCSAY on a congress list or badge, is a convention for showing which name is the family name, not a rule. Capital letters has the rest.