How to get a coworker to stop her personal phone conversations?

I share a small office with another employee who regularly has extended (often longer than an hour) phone conversations with her friends. It should be noted she tends to raise the volume of her voice when she's on the phone. Her desk is about 5 feet from mine, and it is beyond annoying. She is a very sweet person who is VERY sensitive to criticism from a guy, mostly for cultural reasons. This is really the only fault of hers that bugs me like this. The last time I made passing reference to her "loud phone voice", she was apologzing to me for a week about "having bothered me". She and I are really the only people in this part of the office, so no one else notices it. As a footnote, I should mention that she works her tail off, so it's not as though her chatting affects her productivity. How can I broach the subject without hurting her?

You already mentioned that your co-worker is a very sensitive and apologetic person so i really don't see how you could let her know about this without hurting her. Just tell her politely and if she still felt hurt, it's not your fault, it's her fault for being too sensitive and repeating what you have told her before this. In working world, if one were too sensitive, he/she is going to suffer , you co-worker needs to be more open in her thinking , it's for her own good

Tell the boss everything you just said.

Maybe when it appears that the call is personal, you can say, "Sounds like it's a personal call, should I step out for a minute?" Surely she would get the hint that she can't keep you outside too long and prevent you from doing your work.

I wouldn't say that her phone conversations bother you in general, instead say something during one of these conversations about how with the specific thing you are doing, you are finding it hard to concentrate so could she just quiet it a little.

Do that once or twice and she should become more sensitive to how loud she is being and (ideally) tone it down all the time.

There is really no good way around that- you could go to personnel (if your company is big enough to have such a department), and have them say something to her, but that may be worse than talking to her yourself. If she is that sensitive when it comes to criticism, it may embarrass her more to hear it from a "higher-up". What's more, since you said you two are the only ones in your area, she'll know that you're the one who complained. This may put strain on your working relationship, since not only is she embarrassed for having bothered you, she now knows that you're uncomfortable talking to her about such issues.
Just tell her as politely as possible that these conversations bother you, and she should save them for breaks and lunchtime. You'll feel awkward, and she may be embarrassed, but it's better to do it now than resent her later.

If she is talking loud enough for all to hear, what you can do is talk to her about a conversation she had. If she talks about going to the store, when she is done with her conversation, ask her what store she is going to. If it gets too personal, like she is talking about how she could be pregnant, talk about that.

Since you like her and are concerned with her feelings, then just tell her just like you did in your question. Let her apologize if it makes her feel better.

show her this question.

Her chatting does affect her productivity. There's no way it doesn't. I can picture the type of personality you're describing - the profuse apologies make you wish you'd never said anything at all, right?

Either tell her that you heard they're cracking down on personal calls and you don't want her to get in trouble, or report her to her supervisor. Either way, they should know how she's spending company time.

...make your boss aware that this is happening. He will check the phone bills, and when he sees this, will take care of this issue, and you stay clean....

Don't do your bosses work unless you get his salary also....
if nothing is done, then document the calls, with dates and times, just in case you ever have any problems.