Great question. I've always pronounced it /Swa:/ or sometimes /Sva:/, but I looked up the word in Klein's Etymological Hebrew Dictionary and here's what he gives: ShV’ (that's shin vav aleph). With points to indicate vowels you get /S@va’/ with the schwa sound coming between the /S/ and the /v/. Etymology: "Borrowed from Syr. /S@veya’/ (= the seven points), lit. 'even' or 'equal' (points), name of the accent mark [here's a glyph of schwa which looks like our colon under the letter in question], which corresponds to the Heb. accent /zakif/. Syr. /sh@veya’/ derives from Syr. /sh@va’/ (was like or equal), which is related to Heb. /shavah/ (was even smooth or like)." Some medieval Hebrew grammarians spelled schwa with a beth instead of a vav, but it would have been pronounced the same, though changing the words numerological value. So both of us were pronouncing "wrong". Especially since there's a glottal stop at the end.