Cow tongue is not...bad. The most important part is cleaning it - it looks fucking terrible, and it's really hard to tell what you have to get rid of and what you have to keep. You actually need to scrub it too, and then put it in cold water to soak for hours, making sure to change the water whenever it starts looking cloudy.
You don't actually boil it, but simmer it for a rather long time. (2-3+ hrs?) You do the same thing you would do when making stock - aromatics, peppercorns, mirepoix etc.
The *only* time I've ever had cow tongue I prepared it that way, then it went into a lengua, which is some latin soup.
We also subbed it into philadelphia pepper pot soup, which normally includes tripe, but I can't stand it. The cow tongue was not bad in it.