Query: Why the plural in Spanish "Buenas dias," etc.? (OT)

[Peter Richardson]

Sounds like the common disappearance of final -s in various versions of
Spanish. (e.g. ?Como e-ta-? (<estas)

> think "Buena noche."  Whether this is an adoption of singular forms or part
> of a larger phonological phenomenon whereby final s is lost, I don't know,

PR