>I just ask because for instance you have in
>Romanian too, the form of "splai" in Oltenian dialect which is the
>cognate of literary form "splasem".
There ain't no such thing like "Oltenian dialect".
"spãlai, spãla$i, spãlã..." is not only (more) typical of certain
Romanian *subdialects*, but is at the same time high-style standard
Romanian. This is the simple Past Tense (i.e. the Perfect) of the
verb "a spãla - spãlare".
(It's only a (urban) legend that the usage of this Past Tense
is limited to the province of Oltenia.)
Whereas "spãlasem, spãlase$i, spãlase...", is the Past Perfect
Tense (plusquam-perfect). It is also standard Romanian.
(There are 4 Past Tenses: (1) Praeteritum "spãlam"; (2)
Perfect "spãlai"; (3) Composed Perfect "am spãlat" [which
corresponds to the English Present Perfect, but which, in
Romanian, it's a Past, not a Present, Tense]; (4) Plusquam
Perfect "spãlasem". These forms, I chose here are for "eu",
i.e. "I washed & I had washed" + "I was washing & I
have been washing".)