If you have a localized license (e.g., Archicad 26 French), switching to another language is the matching localized or multilingual version.
★★★★☆ (reliable but inconvenient) For unsupported workarounds: ★☆☆☆☆ (not recommended for production work) archicad 26 change language
Managing Application Language Settings in Archicad 26: Procedures and Technical Considerations If you have a localized license (e
Archicad 26 (and other recent versions) handles language settings differently than typical software. The language is determined during installation. Archicad 26 French)