"He should have said that."
Translation:הוא היה צריך להגיד את זה.
Well, the Biblical form אֶמֹר (if combined with לְ־, the laryngal was lost: לֵאמֹר) was replaced in Mishnaic Hebrew analogous to the future form יֹאמַר he will say by the form לוֹמַר. Although modern Hebrew usually prefers the Biblical forms of the infinitive (compare לָקַ֫חַת to take and לָלֶ֫כֶת to go with the Mishnaic forms לִיקַּח and לֵילֵךְ), לוֹמַר was exceptional in prevailing in Modern Hebrew, probably because of its sheer omnipresence in Middle Hebrew texts. The Biblical form לֵאמֹר is very restricted in use and is mainly used nowadays as a quotation marker for the opening of direct speech (similar to many Biblical passages) in high registers, especially in a legal context: בַּסָּעִיף אַרְבַּע לַחֹק נִקְבַּע לֵאמוֹר in paragraph four of the law it is stated that...
Well, Biblical Hebrew had the simple infinitive אֱמֹר (in Ez 25.8 אֲמֹר), but prefixed with לְ־, it always contracted to לֵאמֹר. Like in לֵאלֹהִים to G-d, it must be quiescent, because you could not close an unstressed syllable after a long vowel with a consonant. Silent etymological אs are not rare, think of רֹאשׁ and לֹא not, even in cases like יֶאְסוֹר he will tie up, were א closes a short syllable, I would not swear that it was still pronounced yęʔˈsôr
So, these two sentences came one after another, with the same English translation: הוא היה צריך לומר זאת and הוא היה צריך להגיד את זה. If they both mean the same thing, does it matter which one I use? All I really want is to be understood. No one is grading me. That's way in my past.