When do you use "o" and "a" for nouns and adjectives?
Does llamo also change according to whether the speaker is male or female?
If e.g u are introducing a mixed group of men and women - what will be the form when you say, e.g their names are.....in Spanish? Can you maybe also give another example of a noun/adjective that would relate to both men and women in the group by way of illustration?
The verb llamar does not change depending on the gender of the speaker, but rather is conjugated like other verbs: me llamo (I call myself), te llamas (you call yourself), se llama (he calls himself), nos llamamos (we call ourselves), etc.
For a group of people you could say, "ellos se llaman..."
Verbs are, at least in my experience, not affected by the gender of the speaker. So, it would follow that only descriptive terms (nouns, adjectives, etc) are changed based on the gender of the person speaking/being spoken to. Por ejemplo: Estoy confundido, pero mi novia está confundida. Y estamos confundidos.
This is a little tricky.
In Spanish you typically don't say "my name is", but rather "I call myself".
So in this case, the llamo is really the verb "to call", conjugated for the first person.
Me llamo Sylvester = I call myself Sylvester, not My name is Sylvester.