I'm gonna do my best on this, because at one part I just got really confused.  And I speak spanish, you speak portugues so I'm assuming grammar is essentially the same so I can explain one thing I noticed..  Here it goes.

Correction in parenthesis. 

Winter

First day of the (the = wrong place) winter in Brazil, today (today doesn't need to be here) a (all) the subjects more comment in (commented more on) twitter is (that it is the) first day of the (the = wrong place) summer. Is (It's) funny (to) think that each place is complet(e)ly dif(f)erent of (from one) another.

Now without parenthesis:

On the first day of Winter in Brazil, all the subjects comment more on Twitter that it is the first day of Summer.  It's funny to think that each place is completely different from one another.  

On the last sentence, I noticed you only put "is."  Now in Spanisha and I'm assuming Portuguese, you can say "es la/es el"... stuff like that.  In English, you *need* the direct object which is "it".  You can combine "it" and "is" to make "it's" and that would make more sense.  

Hope I helped out!!!  I wish someone would help me out with Hmong, but it's such an uncommon language that I don't think many people on here speak it... :/