Both spee-sees and spee-shees are acceptable.
How do you pronounce it?
SPEE-SEES…unless I’m just talking about the female half, then it is SPEE-SHEES.
I shay ‘shpeeshees’ shometimesh, if I have shomething in my mouth while I’m shpeaking, like perhapsh a shucker.
Am I the only one saying speckies?
Very possibly yes. I use the first with a slight emphasis on the first syllable.
I pronounce it /ˈspiːsiːz/ .