Castellano Medieval:
De los sos ojo tan fuerte mientre lorando
tornava la cabeca y estava los catando
Castellano Moderno:
Llorando tan fuertamente por los ojos
ya ha vuelto la cabeza y los estaba oberservando
Your translation seems excellent. Just a very minor correction (and it's a matter of opinion). I prefer "volvía la cabeza", or better (en este caso) "volvió la cabeza" or (judging by the sense of the prhrase, a freer translation, but maybe more accurate) "había vuelto la cabeza".
Of course, I believe "ob
eservando" seems to be a tipying error. :p
Words I'm unsure on:
alcandaras: like pecho???
ca mucho avie grandes cuidados: "porque tenia grandes preocupaciones???"
diestra: derecha?? (que viene de directu?)
siniestra: izquierda?
alcandaras: I never heard that word. However, I read "alcán
tara". I believe (long time since I read it) it's some kind of recipient.
Maybe related with "cántaro", remember that we need to separate the particle "al" or "el" in arabic origin words.
I have seen in some antique poems and comedies relate to womens' breast, poetically, as "alcántaras", I believe, so it could mean "pecho" in some way.
"ca mucho ..." Maybe yours is perfect, and that's the first I thought. But if it's like "C'a mucho..." ("Que ha mucho...")then it would be "Que desde hace mucho tiempo tenía grandes preocupaciones".
Diestra and sinistra OK. They both come from latin, unlike "Izquierda", which comes from basque. Diestra from: dexter, dextra (derecha). Siniestra from sinister, sinistri (izquierda).
I believe I must have somewhere at home my latin-spanish dictionary, but I don't think I can find it easily. Anyway, I don't think it explains the evolution of words. Sorry I can't help with that.
BUT, in the
Real Academia site , you are given a brief note on the word's origin, like the ones I posted above, which maybe could be enough.