thanks for contacting and for the debug information and sorry for any delays.
I do not understand french too well, and cannot reply in french.
Do you mind if we change to english?
Regarding your issue, if I understand this correct, the language checkbox does not appear.
Looking at the plugin list, I think the problem is that the bridge plugin for WPML is missing.
Please install the WPML Addon for the import, WPML All Import. This is the plugin that you need to be able to import as described in the documentation.
You will find it in the download area.
Or you can also install it with the WPML Installer in Plugins > Add new >commercial tab