Differences

http://dictionary.cambridge.org/grammar/british-grammar/speak-or-talk

https://www.EnglishForward.com/English/TalkVsSpeak/kjhk/post.htm

anonymous

What is the difference between speak and talk?

There is no profound or complicated explanation. It's often just a matter of personal preference. Only repeated exposure to many different expressions with 'speak' and 'talk' will clear up some of your confusion, as many usages are purely fixed idioms, and there may be certain usages that don't