Yes, you have to add two lines in the file /usr/local/bin/homegenie/html/pages/control/widgets/homegenie/generic/locales/en.json as in the fr.json :
"control_module_off" : "Off",
"control_module_on" : "On",
"control_module_close" : "Close",
"control_module_open" : "Open",
"control_module_calibrate" : "Calibration",
I don't know why if the local data does not exist in the default file it take the value from fr.json.
Cheers
Dani