と (to) vs に (ni) in a phrase like "I am speaking with/to"


I've heard the following two sentences and I'd like to understand the
differences between the two, if any, and when it is appropriate to use one vs
the other:

> おいしゃさん **と** はなしています
>
> おいしゃさん **に** はなしています

It is my understanding that these both translate to "I am speaking to the
doctor", but what is the difference between `と` and `に` here?




おいしゃさん **と** はなしています is "I am talking _with_ my doctor", whereas おいしゃさん **に**
はなしています is "I am talking _to_ my doctor".

The first one with と is natural in most cases, because when you go to a
doctor, normally both you and your doctor will talk to each other.

～にはなす can be naturally used when you're talking to something that do not reply
to you:

> 彼【かれ】は人形【にんぎょう】に話【はな】している。  
>  He is talking to a doll.

...or what is important is whom you are talking to:

> 私【わたし】はあなたにではなく、お医者【いしゃ】さんに話【はな】しています。  
>  I am talking not to you, but to my doctor!




おいしゃさん **と** はなしています is "I am talking _with_ my doctor", whereas おいしゃさん **に**
はなしています is "I am talking _to_ my doctor".

The first one with と is natural in most cases, because when you go to a
doctor, normally both you and your doctor will talk to each other.

～にはなす can be naturally used when you're talking to something that do not reply
to you:

> 彼【かれ】は人形【にんぎょう】に話【はな】している。  
>  He is talking to a doll.

...or what is important is whom you are talking to:

> 私【わたし】はあなたにではなく、お医者【いしゃ】さんに話【はな】しています。  
>  I am talking not to you, but to my doctor!

