More 3rd Party Localization Tools
SystemFonts
System utility to replace default system fonts in most applications. Not entirely reliable and with some cosmetic glitches, i helps to enable Czech character set in Dates, and other useful places. Setting "View update" redraws the screen with new settings immediately, otherwise a restart is required.Found in GNUE's Junk Box (offline?).
Usage: install to Newton, open Preferences and in System Fonts choose a custom font.

UniNames
This utility adds a font setting to Names preferences. By Richard C. L. Li, found on Hong Kong Newton User Group pages, now unfortunately off-line.
Usage: install to Newton, open Names, "i" menu, choose UniNames Preferences, set your preferred fonts.

NotesViewPatch
As above addition, NotesViewPatch allows font face and size for titles and overview mode in Notes. Also very useful for the non-ASCII crowd. By Tomoyoshi Murai.
Usage: after installing open Preferences, choose NotesViewPatch, and pick your font.

Newt-Win Text Conversion
Word macro to convert Czech documens to Mac Roman (Newton-compatible) and back. Authored by Granate Apple company, R.I.P.
Usage: copy template "konverzeNewtWin.dot" to your shared template documets, open with Word and allow macros, paste your text to a new window and push Win-Newt/Newt-Win button to your heart's content.