in general, when your auxiliary verb is avoir (ont etc), the past participle does not agree with the feminine subject (so elles ont parlées would be wrong).
Therefore in you example:
ils ont parlés and elles ont parlés are both correct
However when the auxiliary verb is être (sont etc), the...
I'm going to lead a little discussion at a weekly christian young adult get together. I was wondering what some good topics were to speak on. I was thinking about something how being a good friend can be more of an example of being a Christ-like figure than throwing bible verses at people. But...