Oh, here's some true story to better illustrate your comment.
Coincidentally, I am a fireman, and once some colleagues of mine decided to make a shirt. Wanting to express themselves in the cool English language - but not being quite acquainted to it - they inadvertently applied Portuguese rules to it...
Because of the verb form:
- Eu sou
- Você/Ele/Ela é
Since "Eu" doesn't share the verb form "sou" with any other personal pronoun, it can be omitted from the sentence. In the third person singular, the pronoun is almost always mandatory (at least at first) to distinguish between Você, Ele and Ela.