'May I speak to....' vs 'May I speak with...' vs 'May I talk to...' [duplicate]

Nice question, +1.

I think you're right even if they are pretty much interchangeable (consider the context!), and this is shown in the dictionary too.

Even though there are some subtle differences:

• Talk to: This one when used like VERB, has the acception of strong discussions, negotiation, or even "(talk to) reprimand or scold (someone)".
  Plus talk has many familiar uses (according to the OED).

• Speak: This is inside the entry about the verb "to speak" - To speak to another by means of a telephone; ― speaking (where ― is a speaker on a telephone), phr. used by the speaker to announce his identity.

So, if you are going to phone to someone on the phone, then "May I speak with...?" sounds like the most appropriate one.