Don/Doña: Similar to Sir/Madam but sometimes meant to convey someone's high rank in society. This honorific is usually reserved for elders.
Nena/Nene: Little child. It's commonly used as an endearment or when you're frustrated with someone.
Patron/Patrona: Boss (Male/female)
Señor/Señora: Sir, Madam
Usted: Formal way of saying "you". Hard to work into the translations as English has no equivalent. Usually I just add a "Sir/Madam" at the end to convey formality.
"Te Quiero" is appropriate for any love (lover, friend, parents, siblings)
"Te amo" is specifically romantic.
It can indicate smallness: Casa means house and casita means little house.
It can indicate affection: Ivo will affectionately become Ivito.
Cholito: This is Milagros' nickname. Named after the famous football payer Diego "Cholo" Simeone, it literally means "Little Cholo".
Fierita: This is Mili's name for God. It means someone who is very talented and able.
Bailanta: A night club where only a specific type of music is played (Cumbia). It certainly isn't viewed as a fancy place to be at.
Calenchu: I believe this is strictly Argentinian lingo. Mili has said Ivo is "Calenchu" various times...meaning he's heated/upset because he's been bested at a game or something of the sort.
Chirusa: Someone who is vulgar, ill kept, not very educated. A similar American term might be "ghetto".
Guacho/a: It's a vulgar way of saying orphan but it's also used to mean other things:
1. Someone who is a bad person
2. Used as an expression when someone is lucky