Questions & Answers about Eu disse alô.
Yes. Brazilian Portuguese often allows the subject pronoun to be omitted, so Disse alô can also be possible in context.
But here eu is useful because disse is ambiguous: it could mean I said or he/she/you said. Adding eu removes that ambiguity.
So:
- Eu disse alô. = clearly I said hello.
- Disse alô. = Said hello, but the subject depends on context.