4. Optative W finite verbs have no variable vowel before the personal ending.
I not quite sure what you mean by 'variable vowel'. Can you clarify this?
Meanwhile, permit me a few borrowed observations about optative morphology. This mood can be athematic or thematic. When athematic the optative mood suffix exhibits ablaut - vowel alternation - alternating between [face=SPIonic]ih[/face]
in the singular active and [face=SPIonic]i[/face]
in the dual/plural active and middle. So, looking at the verb [face=SPIonic]ei)mi/[/face]
1st singular present optative active = [face=SPIonic]e-ih-n[/face]
1st plural present optative active = [face=SPIonic]e-i-men[/face]
When thematic the optative mood suffix is always [face=SPIonic]i[/face]
; whence, in combination with thematic omicron, the familiar [face=SPIonic]-oi-[/face]
suffix that we see in many verbs, e.g., [face=SPIonic]lu/w[/face]
But note that by a kind of intrusive analogy you do see thematic forms mixing with athematic, e.g., [face=SPIonic]e)/oij[/face]
, 2nd and 3rd person singular active of [face=SPIonic]ei)mi/[/face]