Original sentence: The heart of the issue is that the terms Bosnian and Bosniak are not interchangeable: Bosnian refers to all three ethnicities of Bosnia and Herzegovina, while Bosniak refers only to Bosniaks
Edited sentence: According to Croat and Serb nationalists, the heart of the issue is that the terms Bosnian and Bosniak are not interchangeable: Bosnian refers to all three ethnicities of Bosnia and Herzegovina, while Bosniak refers only to Bosniaks