"The woman sees a boy."
Translation:Ābra taobe urnes.
What is the difference between urnesi, urnen and urnes? In what cases you should use them?
They're all conjugations of the same verb for a different person and number.
urnen - I see, urnē - you (singular) see, urnes - he/she/it sees, urnī - we see, urnēt - you (plural) see, urnesi - they see
So, it's like how in English you use an -s for verbs in the third person singular, only you have a different form for all six version. It's similar to Spanish in that way, and also because you don't need a personal pronoun to indicate the subject, since the verb already makes that part clear.