That'll just delay the spamming by 24 hours, and would be pretty annoying if you registered because you want help, and then have to wait 24 hours to make a topic.
There shouldn't be any foreign-language posts here, as this is an English forum, and everybody should talk English here, so no need to worry about that. But I agree with you on the subject having to be ASCII only, however, the spammers will just change their posts to one with an ASCII-only subject.
I agree, there have been spammers spamming posts on the forum for a couple of days in a row now, and when there isn't a mod/admin online to ban/remove them, they'll stay there until one comes online.