Both are common. A Google Ngram search shows that "speak to" is about four times more common that "speak with" for both American and British English. Here is the chart for British English. https://books.google.com/ngrams/graph?content=speak+with%2Cspeak+to&year_start=1800&year_end=2000&corpus=18&smoothing=3&share=&direct_url=t1%3B%2Cspeak%20with%3B%2Cc0%3B.t1%3B%2Cspeak%20to%3B%2Cc0 The Oxford Learner's Dictionariers website is an excellent resource. It shows "speak with" as a North American usage. speak - verb https://www.oxfordlearnersdictionaries.com/us/definition/english/speak_1?q=speak have conversation ​ [intransitive] to talk to somebody about something; to have a conversation with somebody speak (to somebody) (about something/somebody) I've spoken to the manager about it. The President refused to speak to the waiting journalists. (especially North American English) speak (with somebody) (about something/somebody) Can I speak with you for a minute?

Thank you so much for you help!!! I appreciated it a lot! You explained that very well.

Speaks to usually means a conversation. Speaks with can mean the same, but it is often used to mean to speak to someone a particular person about a particular subject, or complaint, or annoyance etc. If you are in a school and the teachers says "The school governor wants to speak with you", it usually means bad news or he has something to tell you. "the school governor wants to speak to you" would imply only a chat, but this use is dying out in the UK you might still come across it. Apart from that they are the same

There's no difference, except "speak to" would be considered grammatically correct.