לספר means to tell. You can say: לספר סיפור which means to tell a story. But you cannot use the verb לומר in this context. While in your example I wouldn't use the verb לספר. So לומר or להגיד are good translations for the verb "to say" but לספר is "to tell". More examples: הוא סיפר לי שאשתו בהריון. (He told me his wife is pregnant) "היא לא בבית עכשיו", הוא אמר. (She's not home right now, he said). סבא שלו אוהב לספר על ילדותו. (His grandfather likes to "tell" about his childhood - the translation is intentionally literal).

you can say too אנחנו לא יודעים מה השעה. אתם יכולים להגיד לנו

And by the way - the right pronunciation of the verb is "LESAPER" (: