As the Holy Roman Emperor Charles V, said:

I speak Spanish to God, Italian to women, French to men, and German to my horse.

No mention of 'English to my beloved hippopotamus'.

I met a guy called Neil, whose German girlfriend's family affectionately (I think) called him Nilpferd, 'Nile horse', i.e. hippopotamus.

Pitfall coincidence time:

This was while working at the Asterix warehouse, mentioned in one of my first interactions with @pjogley, founding publican of this hostelry, commenting on his article about reading books as a language learner.

And said Neil/Nilpferd might possibly have been on the same high school German exchange as Philip's wife.

Though really this is just the same coincidence rehashed.