Tongue-tied in a sentence as an adjective

Yes it is. Example - sometimes people are "tongue-tied" - they know what they want to say, but can't remember the word for that.

Two of our children have been identifed as tongue-tied by midwives in hospital.

Sometimes the baby is tongue-tied, like ours, and the breastfeeding advice is unlikely to work until that is fixed.

Clear me of that manifold guilt which makes me the laughing-stock of fools, tongue-tied and uncomplaining, because I know that my troubles come from thee; spare me this punishment; I faint under thy powerful hand.

The credential still is meaningful - how much spadework is there to training an educated subject vs one with no vocabulary, no facility with theory, no proven ability to learn?So yes, hire a successful college grad over, say, a tongue-tied inexperienced person without a degree.

Tongue-tied definitions

adjective

unable to express yourself clearly or fluently; "felt tongue-tied with embarrassment"; "incoherent with grief"

See also: incoherent