Are the pronouns used in Portuguese when speaking? (Eu, você, ele/ela, nós, vocês, eles/elas) For instance instead of “Eu não falo português” could I simply say “Não falo português” ?

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The pronoun can be omitted when it can be implied from the verb.

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For example, this is conjugation for "falar" in the Present Tense:

Eu (I) falo...
Você (You) fala...
Tu (You*) falas...
Ele (He) fala...
Ela (She) fala...
Nós (We) falamos...
Eles (They) falam...
Elas (They) falam...
Vocês (You - plural) falam...

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When you say:
"Não falo português" ✅
The subject can be implied from the verb (even though it's hidden), because the only pronoun which accepts the verb form "falo" is "eu". It's a pretty acceptable and suggestive sentence.

However, you shouldn't say:
"Não fala português" ❌
Because you can't tell if the subject is "ele", "ela", "você", etc. In this case, you shouldn't hide the pronoun in order to make it clear to the listener who is being spoken to/about, unless the subject can be implied from the context that the sentence is uttered in.

Hope it helps! ^^