I have never ever seen a menu anywhere in the world where testicles were on as sweetbreads. Or any literature of any kind that describes them as such, have you?

I know that Wikipedia isn't infallible, Bruno, but in this case it - and degsy - are correct:

Sweetbreads or ris are culinary names for the thymus (throat, gullet, or neck sweetbread) or the pancreas (heart, stomach, or belly sweetbread) especially of the calf (ris de veau) and lamb (ris d'agneau) (although beef and pork sweetbreads are also eaten).Various other glands used as food are also called 'sweetbreads', including the parotid gland ("cheek" or "ear" sweetbread), the sublingual glands ("tongue" sweetbreads or "throat bread"), and testicles (cf. Rocky Mountain oyster).The "heart" sweetbreads are more spherical in shape, and surrounded symmetrically by the "throat" sweetbreads, which are more cylindrical in shape.

You are correct, Wikipedia can't be trusted.

But I am also correct that in this instance it is right. Testicles are also known as sweetbreads in certain parts of the country.

Three of my dad's favourites:
Head cheese (zure zult)
Blood tongue
Balkenbrij (like the American scrapple which has Dutch origins. Haggis comes close.)

BTW In the Netherlands sweetbread (zwezerik) exclusively refers to the thymus of calves.

I bought some "Pigs Cheeks" from the forgotten cuts range in Waitrose. I still have them in deep freeze, I haven't got a clue what they taste of or what to do with them!