How to pronounce Caissa? I imagine that it might be pronounced

1) kye EE suh

2) kah EE suh

3) KAY suh

4) KYE suh.

Which is it? Or perhaps there is no established way and one shouldn't care too much.
Short version:

I think that your best bet is probably option 2: "kah EE suh" (similar to the pronunciation of "naïve"). The phonemes match the spelling correctly (particularly the umlauted ï in "Caïssa" [ref. 1]), and it fits with the tonal stressing of multiple Thracian-related [ref. 2] languages.



Long version:

Historically, both Greek and and Turkish (largely Hittite and Assyrian influences, in Thracian times [ref.s 3 &amp; 4]) would appear to have likely had the strongest early influences.

Satemization of the Thracian language [ref. 5] would indicate the initial “C” to typically be an “s” sound, though it seems that in the case of “Caïssa” it was more likely a “k” sound.

Given the remnants of the Thracian language available to us [ref. 6], there seem to be insufficient data to ensure “correct” pronunciation.  Thracian words seem [to me] to be equally likely to be most closely related to Latin, Greek, and several Balto-Slavic languages.

If Gottfried Schramm's derivation [ref. 7] is correct, then his Bessian-Albanian link would indicate that the “i” is indeed a “long e” (ï) sound [ref. 8].



References:


https://en.wikipedia.org/wiki/%C3%8F 
https://en.wikipedia.org/wiki/Ca%C3%AFssa 
https://en.wikipedia.org/wiki/Thracians 
https://en.wikipedia.org/wiki/Turkey#Prehistory_of_Anatolia_and_Eastern_Thrace 
https://en.wikipedia.org/wiki/Centum_and_satem_languages 
https://en.wikipedia.org/wiki/Thracian_language#Remnants_of_the_Thracian_language 
https://en.wikipedia.org/wiki/Thracian_language#cite_note-3 
https://en.wikipedia.org/wiki/Albanian_language#Vowels