A few etymological curiosities for Alvin.
I've checked the etymology of Alb. det 'sea'. All my sources
support *dHeub-eto-s (from *dHeub- 'deep') as the protoform. Alb. thellë 'deep',
which you asked me to explain, is derived from *k^ouH-ilo- 'empty, hollow,
cavernous', which is an adjective derived from the word *k^ouH-r 'cavern,
cavity' (these English words are also related to the same root via Latin). As
you may remember, PIE *k^ > Alb. th.
The mysterious -di:te: in the name of Aphrodi:te: can hardly
be anything else than the feminine form of PIE *dih2-to- 'bright' from the verb
root *deih2- 'shine' (related, BTW, to *dje:us 'daylight, Sky God', cf. Gk.
Zeus, Skt. Dyaus, etc., which is a different extension of the same morphological
base *dei-). Whether Aphro-di:te: was originally "as bright as foam" (the most
natural-looking but not necessarily true etymology) or "something-else-bright"
is hard to ascertain. If it's a comfort to you, Albanian ditë 'day' is supposed
to come from the related noun *dih2-ti-s 'brilliance, shining', which means that
it is also a member of that family of words.
Piotr