Sberna is a surname of Swiss-Italian / Franco-Provençal origin (found spelled as Bernaz in the Chablais) (Substrate Pre-Roman "Celtic").
Etymology
Of the word "Vern", gwern or berula (berle), it mean "alder tree" or place of alders. The word derivate of a Celtic person that live where alders grew.
Galo dialect drift Italico (Lombard language), mixture of French, Italian and German or maybe the (Romansh) spoken in the Canton of Grisons (Graubünden (Switzerland), Lombardy (Italy) and Canton of Ticino (Switzerland), whose etymology seems to be very old and date back to the time of Gaul, which was inhabited by Celtic tribes, between present-Switzerland, part of Belgium, part of Austria and northern Italy.
The word is written in that dialect s'bèrna and bèrna and the accent described the letter "e" to rule e: (i.e. as ee). Its dialectal meaning is skinny and ugly (magro e brutto in Italian), indicating that the name derives from a physical appellation of people, although it is a hypothesis.
This Pre-Roman dialect (the Swiss Rhaetian or Raetia) is one of four official languages of Switzerland by the Swiss German, Swiss Italian and Swiss French.
The Eastern Alpine dialect is also spoken in parts of Sicily, entering there in time of the Norman Conquest (Viking).
According to Gerhard Rohlfs it derives from a Sicilian word sberna which meant alder whereas for Giuseppe Gioeni it means big cloth cover (cf. burnous).