How does the Motivational Speech spell work?

Question

Motivational Speech (Acquisitions Incorporated, p. 77) says that you inspire a group of people to greatness.

You address allies, staff, or innocent bystanders to exhort and inspire them to greatness, whether they have anything to get excited about or not.

Motivational Speech further grants specified statistical benefits attributed to what inspiration entails:

Choose up to five creatures within range that can hear you. For the duration, each affected creature gains 5 temporary hit points and has advantage on Wisdom saving throws. If an affected creature is hit by an attack, it has advantage on the next attack roll it makes.

But is not explicit about what greatness entails. So what does greatness entail? To which greatness are you inspired? Is the greatness chosen by the caster, the DM because it is DM-fiat territory, or by some other circumstance?

Answer 1

I'd say "greatness" is whatever the caster is trying to encourage their targets to accomplish in that moment.

Essentially, the verbal component is you trying to give them a motivational speech for 1 minute, meanwhile weaving in a magical component that consists of the mechanical effects of the spell.

It doesn't involve any element of compulsion, so even though you've given them an inspiring speech encouraging them to do the thing, they could go do something else with the buffs you just put on them. It's just flavor.

Answer 2

The implication of the spell is that the "inspiring to greatness" is what leads to the effects given starting in the next line.

Choose up to five creatures within range that can hear you. For the duration, each affected creature gains 5 temporary hit points and has advantage on Wisdom saving throws. If an affected creature is hit by an attack, it has advantage on the next attack roll it makes. Once an affected creature loses the temporary hit points granted by this spell, the spell ends for that creature.

It's certainly a tentative connection given that it's hard to imagine how inspiration could directly lead to any of these things, but in the end it's a magical effect and doesn't have to make complete sense.

In any case, it fits the very common spell description formula of describing the effects/spellcasting process more in game/fiction terms first and then describing what that means in explicit mechanical terms immediately after. This is a form that many many spells use.

Besides that, if there are any other effects that "inspiration to greatness" would entail, the spell doesn't tell us and thus it will be completely up to the DM to decide.