Hunspell is a free software and widely used in various applications you might be using every day. This option makes it possible to add hyphenation for about 90 languages that are not in the standard installation of InDesign, including Icelandic. Many InDesign users have trouble installing what it takes to activate Hunspell for their language. That is why I made the Hunspell is_IS installer for InDesign. I had not really thought about it untill it was pointed to be that InCopy needed a similar installer. So I made one. You can download it using the link at the bottom.
This Hunspell is_IS installer for Mac version of InCopy CC 2015 will not work on previous versions.