I have a site that is translated in English and French - can't change "Home" link in menu
Most likely, the "Home" menu link is coming from the UI text in Drupal Core.

You should be able to enable the "Interface Translation (locale)" module and then obtain .po or .pot files for the respective language (as described on the Drupal.org internationalization page). 

Refer to https://www.drupal.org/node/1814954 for information about editing the .po/.pot files and https://www.drupal.org/node/314231 for info about obtaining them.