Available languages for IrfanView version 4.23 (or 4.22)

English (always included)
German/Deutsch (schon integriert, hier die deutsche Hilfe-Datei)

Czech/Cesky
Turkish
Slovak
Chinese
Nederlands
Russian
Portugues-Brasil (help file included)
French
Spanish
Polski
Italian
Hungarian
Japanese
Hrvatski
Slovenscina
Ukrainian
Dansk
Korean
Uzbek
Estonian
Arabic
Svenska
Hebrew
Bulgarian
Persian

Link - IrfanView languages