[Beagle8U]

The better question is WHY would anyone want to learn a dead language?

[kenavi]

4 the after-life??

[Verginius Rufus]

Dead languages are worth learning if they have a literature--such as Latin or ancient Greek.

Cornish is a Celtic language formerly spoken in Cornwall, in SW England. It became extinct in the 18th century but apparently there are people today trying to revive it. Manx was spoken on the Isle of Man until a few decades ago when the last speaker died. It was related to Irish Gaelic. I suppose it would be useful if you had a Manx cat which refused to respond to commands in English.

A Romance language called Dalmatian died out in 1898 when the last speaker died. About 1% of the population of Switzerland speaks Romance dialects known as Rhaeto-Romance--they are so few in number it's thought that the language may eventually die out.