Iuvenis means "young man", yes, and, according to my dictionary, Cicero uses it to mean citizens who fit for military service. But Suetonius apparently uses it for "young people," regardless of gender; and Livy uses it to mean "young woman." So it seems to me that other acceptable translations here are:
(The) young people save (the) cities. (The) young women save (the) cities.
Then the translation "the youths" should be accepted. I will try it and suggest it as a valid translation.
What mean save the cities? From aliens? Shouldnt servant be translated to serve?
The verb servare means to save. It gives us such words as conservation, preservation, to preserve, to conserve. You're thinking of servire, which means to serve. It's a completely different word. :)
Double check on William Whitaker's Words to make sure: http://archives.nd.edu/cgi-bin/wordz.pl?english=serve
Volgav vitsenanieff nivya kevach varatsach.
Thanks for the expanation, but I still don't get the meaning of the phrase. How the young "save" the cities, and from what? "serve the cities" would make more sense, using the proper verb (servire) you mentioned.
You can save cities from an enemy. It's a fine usage of the verb in Latin.
"The young men serve the cities" would be "Iuvenēs urbēs serviunt". The verbs servō and serviō are conjugated slightly differently.
servāre (to save)
servō / servās / servat
servāmus / servātis / servānt
servīre (to serve)
serviō / servīs / servit
servīmus / servītis / serviunt