He was right - in Italian
Giacomo, the first sylable is stressed.
However, things are really ambiguous. My conclusion in advance:
If
Giacomo corresponds to
Jacob and Greek was the source, we may assume "Jah-KO-mo".
If
Giacomo corresponds to
Jacob and Latin was the source, we may assume "JAH-ko-mo".
"Jah-KO-mo".
If
Giacomo corresponds to
James and Greek was the source, we may assume "JAH-ko-mo".
If
Giacomo corresponds to
James and Latin was the source, we may assume "Jah-KO-mo".
This is a byblical name (
Jacob) and there are at least two persons with the name
Jacob so that I cannot say of they have really the same name. Here are two text excerpts originally written in Greek.
[Ad Romanos, 9:13]
"Sicut scriptum est Iacob dilexi
Esau autem odio habui."
"As it is written,
Jacob have I loved, but
Esau have I hated."
This
Jacob is mentioned in the Old Testament also. In the Greek text, the stress is on the "o" (it is an omega there). This name is not declined neither in Greek nor in Latin - no special accusative forms are used in this case. This name is not changed in the English translation.
[Mathiew, 10:2]
"Duodecim autem apostolorum nomina sunt haec: primus
Simon qui dicitur Petrus, et
Andreas frater eius, Iacobus Zebedaei, et
Johannes frater eius, .."
"Now the names of the twelve apostles are these: the first,
Simon, who is called Petere, and
Andrew his brother,
James the son of
Zebedee, and
John his brother, .."
Here, the name
Jacobus is declined in both Greek and Latin. In English, it is translated as
James. In Greek, the "o" is omega again (a long vowel) but the stress in Greek is on the "a". In Latin, nevertheless, the stress should be on the "o" if it is long! Thus, I have to assume that Iacobus was pronounced with a short unstressed "o" in Latin so that this name chanhed to
Giacomo (the stress on the "a"),
Jacques (French) and
James (English). Someone may assume the stress on "o" in Latin (as it should be according the rules) and trerefore the stress on "o" in the Italian
Giacomo.
It would be interesting to me if these names (
Jacob and
James, Latin Iacob et Iacobus) are really the same in Hebrew.