jMemorize does not directly provide support for non Roman alphabets. This functionality is usually provided by operating system support, but you may have to install the support for a particular language.

http://www.starr.net/is/type/kbh.html has an extensive list of ways to install language support for several operating systems.

Esperanto: Windows computers don't come with an Esperanto keyboard input method. But you can install an excellent Esperanto keyboard program for Windows called EK: http://www.esperanto.mv.ru/Ek/index.html Many versions of Linux, e.g. Ubuntu, do come with a keyboard method for typing the ĉapelitajn literojn de Esperanto, do ĝuu... :)

Latin: If you want macrons for the vowels (āēīōū), note that most operating systems don't come with a Latin keyboard option, and most other languages don't have those letters. But Maori uses them, so if your OS has a Maori keyboard, you can install the Maori driver to type Latin! (But ȳ (y with macron) appears in a few Latin words also, and the Maori keyboard won't let you type it; you could cut and paste ȳ from somewhere on those rare occasions that you need it, but be aware that many fonts will also not display it.)

Polish: Most operating systems provide ways to type Polish letters. Often there are several choices; probably the one you want will be called "Programmers" or some such, which lets you type AltGr+letter (AltGr+c = ć, AltGr+L = Ł, etc. Note AltGr+z = ż, AltGr+x = ź.