It depends on what she means by talking.
I (prb) kept a record of words. But she had to use the word twice in
Over the years I have been told:
"My 6 month old says "hiya". They say it whenever they see me, so they obviously know what it means": Actually said child was saying "hihihihihihihihihihihihih" because they'd just discovered babbling. You can guess when child said "mamamamamamama" 
One lady at toddler group used to "translate" for her babbling baby starting at about 7 months.
Baby: "babbabababbaba"
Lady: "She just said, she really likes your dress because her favourite colour is blue..."
Rest of us: 
And yes, she was deadly serious.
8 month old who apparently used to ask for a story to be read by sainf "book" when mum demonstrated child was actually blowing a raspberry 
And at the opposite end of the scale, a mother who spoke to me in tears because her ds was not talking at all at 18 months.
Upon talking to him and her I found that he could say lots of animal noises (including some unusual ones) if you showed him the animals, "choo choo" for train, "brmm" for car, and also had several words that weren't totally correct "joo" for "juice", and "bot" for "bottom" (wanting a nappy change), "mama" for "mum"... and lots more. Because he didn't say any words completely correctly, mum thought that they didn't count. He actually was quite advanced and said lots including putting words together.
And if you sing the alphabet/count in different languages they will learn them. They're just different words. how are they supposed to know that it's a different language?
To put a similar comparison, I could say "dd1 was writing full sentences-before she was 2yo".
It's true-of a sort.
What happened was when she was about 20 months she wanted to play on the computer like mummy and daddy. We had an old computer that didn't run any game more complicated than minesweeper, so the only thing she could do was type in word, as she couldn't really handle the mouse.
So it started as a game. She initially started pressing the keys randomly, then she started asking for particular words. So she would say "mummy". ANd I would say "m for mummy, u for umbrella..." while pointing to the right key to press. Soon I didn't need to touch which key to press, and it evolved to her saying a sentence, and me spelling it out.
It was a game just as much as pressing buttons on an electronic game. It resulted in her having "written" a sentence. But actually she couldn't have done it alone, so it wasn't really true writing. Saying she was writing in sentences gives the impression she was using a pencil and spelling it all on her own.