Gem Dragonborn, from Fizban's Treasury of Dragons (p. 11), have the Psionic Mind trait:
You can send telepathic messages to any creature you can see within 30 feet of you. You don’t need to share a language with the creature for it to understand these messages, but it must be able to understand at least one language to comprehend them.
The summon elemental spell from Tasha's Cauldron of Everything (p. 111) says:
[The summoned elemental spirit] obeys your verbal commands (no action required by you).
Can a gem dragonborn use Psionic Mind to telepathically issue commands to a summoned elemental spirit?
I think it hinges on a couple things. One is "verbal". The spell does not say "spoken aloud". You can certainly verbalize in your head without saying anything, I'm doing it now, as I type.
Clearly the elemental understands the gem dragonborn. The question is, do commands have to be spoken aloud to be "issued"?
Obviously, in the end it's up to the GM, but I want to be informed for the discussion.