A footnote in this question states that the tongue is one of the parts of the animal which is given to Kohanim. This led me to wonder if a non-Kohein may purchase or eat tongue? I have seen tongue for sale at kosher butchers before.
The tongue has no inherent holiness. The Kohein may sell it or even give it as a gift to whomever he wants (even a non-Jew). (ShA YD 61:13)