Both Adam and Anna give concise explanations. Think about this: We are having a long conversation about many things. Let's say this is a long conversation about "John". We talk about many things in this conversation: First: we talk about John's job Second: we talk about John's hobbies Third: we talk about John's family Fourth: we talk about John's ability to fish. These topics come in the conversation, and these topics go. So when it comes to (the topic of fishing), we can say that John is an expert. I hope that helps :o)

Adam and Anna are generally making the same point. 'When it comes to...' is used when you want to direct the conversation into a specific point in that topic. 'With regards to.." and 'As for.." does the same thing. The purpose is to point the conversation to a specific point. Example: If you are speaking of love, which is a broad topic, you may want to say a comment about something specific in love. So you might say "When it comes to marriage, I can't deal with that!" Adam's example would work perfectly "With regards to marriage, I can't deal with that." "As for marriage, I can't deal with that." All of these work, and introduce you to this topic of marriage, which is a specific part of love. In this case, Anna's example 'Speaking of' wouldn't exactly fit, because you weren't already speaking of marriage. But you can say "Speaking of love, I cannot deal with marriage." The point is that the function of "When it comes to.." is the same. To direct you to a specific topic in the conversation so you can make a point about it. More examples: If you are speaking of school in general; talking about classes, and friends, lunch etc. But then you might want to make a specific comment on homework, you might say "When it comes to homework, I am terrible at that!" If you are speaking of work in general but then you want to make a specific point, you might say "When it comes to staying late, I hate that!" If you are speaking of how beautiful cars are, you might say "yeah, yeah, that one is beautiful that one is beautiful too, etc. Yeah cars are so beautiful. But when it comes to driving cars, I hate it!" I hope those examples help you see what I mean.

"When it comes to" is used the same as the phrases like "as for" or "on the subject of" or "speaking of". It has a more informal, conversational tone. Mary: "I went fishing last weekend. I think I am good at fishing." Jane: "Oh, really? When it comes to fishing, John is the best!" (or something like, "Speaking of fishing, John is the best fisherman.")

You can easily replace the expression with "With regards to ..." So, your explanation ("When we talk about ...") isn't far off.

- When it comes to fishing, John is an expert. = John is an expert fisherman. - When it comes to learning a new language, some learners like dictionaries. = Some learners like to use a dictionary, when learning a new language. 'When it comes to' is almost never used in spoken American English. I'm a native English speaker, and I have never once said 'when it comes to.' In my opinion, it sounds a bit silly and outdated. In the end, I would not worry about understanding this phrase, because you will never use it.