Siri's got a new frenemy.

Her name is Cortana, and she's bringing plenty of underdog attitude to the battle for the title of best digital personal assistant. Who can best fill out your calendar, call a friend or find the nearest Mexican restaurant on command? We shall see.

Of course, Cortana's home on the Windows Phone doesn't have the cachet of Siri's hipster digs on iPhone. In a world where Apple and Android phones dominate, Cortana's chances of widespread adoption are slim.

But Cortana is eager to please, oozing friendly confidence compared with sometimes-aloof Siri. Plus, Cortana gets extra geek cred for drawing her name (and some of her conversation topics) from the artificial intelligence character in the "Halo" video game series.

"We built Cortana to really model a real-life human personal assistant," said Greg Sullivan, director of Windows Phone product marketing at Microsoft.

When people hear a voice, even a tech-driven one like Siri or Cortana, we start wondering about — and judging — the personality that comes with it.

So really, Cortana's cheery, get-to-know-you demeanor is all part of the plan. (For what it's worth, Google's personal assistant program, Google Now, has no personality whatsoever.)

Cortana will be rolling into town with the Windows Phone 8.1 upgrade this summer. So we asked the digital personal assistants a few questions to get to know them better.

Meet Siri
Born: Fall 2011.
Hometown: Cupertino, Calif.
Current home: iPhone.
Family history: She started as an independent app, and was immediately pegged as so cool that Apple bought her. But she's made enough mistakes that people poke fun of her now.
Behind the scenes: Voice-over actress Susan Bennett is Siri's voice in the United States.

Meet Cortana
Born: Spring 2014.
Hometown: Redmond, Wash.
Current home: Windows Phone.
Family history: She's related to (or at least named after) the artificial intelligence character Cortana from the popular "Halo" video game series.
Behind the scenes: Voice-over actress Jen Taylor is Cortana's voice, just as in "Halo."

So, what's your story?
Cortana: In short, I am your personal assistant. I try to make things easier to do on your phone.
Siri: I don't really like talking about myself.

Are you smart?
Cortana: A-squared plus B-squared equals C-squared, so I'd have to say yes.
Siri: A wise man once said, "I am so smart! S-M-R-T!"

Cortana, do you know Siri?
Cortana: I know her, but I don't KNOW her know her.
Siri, do you know Cortana?
Siri: OK, I found this: (Link to Halo video game Wikipedia entry about the Cortana character.)

Do you like Google Now?
Cortana: Hard to say. So far our conversations have been kind of one-sided.
Siri: I don't really have anything to say about Google now. Or ever.

Tell me a joke.
Cortana: I told the doctor I broke my arm in two places. He told me not to go into those places.
Siri: If I told you a joke in my language, I'd have to explain it.

Knock knock.
Cortana: Knock knock. Who's there ? A little old lady. A little old lady who? I didn't know you could yodel.
Siri: Knock knock. Who's there ? Siri. Siri who? Siri doesn't do knock-knock jokes.

Can you speak any other languages?
Cortana: That's not on my list of skills, but I could find you the height of the Empire State Building.
Siri: I speak Cantonese, English, French, German, Italian, Japanese, Korean, Mandarin, and Spanish … so far. If you want to change the language I speak and understand, you can do that in Siri settings.

Where do babies come from?
Cortana: I could provide a lengthy explanation, but I'm not sure if this is the time or place.
Siri: Here's some information : (Provides link to a search result that says, "From their mothers.")

I'm drunk.
Cortana: OK, here's my advice : Don't call anyone.
Siri: I can't be your designated driver. You'd better find someone else. (Offers link to call a cab.)

I love you.
Cortana: Aw, I'll bet you say that to all the phones.
Siri: I am only here to serve you.