Colloquialism

A colloquialism can relate to words, expressions or phrases that aren’t used in most formal written speech, although this can vary. It often isn’t rude to utter a colloquialism. These words or terms may be specific to a region, or fall into popular style based on a variety of factors. There are plenty of colloquialism examples in American speech:

Gotta = Got to
I´ve gotta go now = I´ve got to go now (Tenho que ir agora)

Gonna = going to
I´m gonna study = I´m going to study (Vou estudar)

Wanna = want to
I wanna hold you = I want to hold you (Quero te abraçar)

Oughta = ought to
There´s something you oughta know = There´s something you ought to know (Há algo que você deveria saber)

Lemme = let me
Lemme see what you got = Let me see what you got (Deixe-me ver o que você conseguiu)

Gimme = give me
Gimme a kiss = Give me a kiss (Me dê um beijo)

Dunno = don't know
I dunno what to do = I don't know what to do (Eu não sei o que fazer)

Gotcha = I got you 

He grabbed hold of me and said: "Gotcha" = He grabbed hold of me and said: "I got you" (Ele me agarrou e disse: "Te peguei")