このえいがは、十八才以上しか見れません, and it just seemed very counterintuitive. Jisho tells me that しか means “only”, so I read the second part as
“18 higher than only cannot see”
…meaning only 18+ people CAN’T see this movie, i.e. the opposite of what it actually means. Could someone please help me clarify the usage of しか + negative verbs?
しか means “except for”, but translations usually make it sound more natural by turnig it around and using “only”. That’s probably why Jisho says the meaning is “only”
As for this movie, except for those older than 18, cannot watch.
becomes: As for this movie, only those older than 18, can watch.