Start by loading the plist into memory. You have an array of dictionaries so you should use NSArray
NSArray *translations = [[NSArray alloc] initWithContentsOfFile:filePath];
Now just use NSArray
filtering methods to get what you want.
NSArray *matches = [translations filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"self CONTAINS[cd] %@", searchTerm]];