I feel like this might be more easily solved by using words instead of creating a bunch of complex behavior that the user must figure out.
Instead of a list of languages with the title "Languages" and a pale, tiny "Install" button, why not something like this?
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Which languages would you like to install?
* English
* Français
* 日本語
* tlhIngan Hol
* Lobjan
(Install)
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The "install" would initially be inactive, and transition to an active state when one or more language(s) is selected.