| Subject | English | Spanish |
| comp., MS | fallback language | idioma de reserva (The base language that appears when a string has not been localized into a partially localized language) |
| comp., MS | ultimate fallback language | idioma de reserva final (A final fallback language independent of user and system preferences. Resources for this language may either be built into the language-neutral portable executable, or otherwise guaranteed (through the installation process) to be always available) |