As to the profanity, there's two types.
Abusive language is a red card.
If the profanity is directed at some one, the referee should be sending them off instead of 'giving them a worthless yellow'. Nowadays, profanity is used fairly commonly. With the difference between the two organizations, don't be surprised to see some referees that feel the red is too harsh. The local parents did not help by questioning everything that happened on the field and one of the referees really hurt his credibility by talking on his cell phone for about 15 minutes during play. Their league is extremely competetive, but without the attitudes.