A pair of shoes are the two shoes that go together. A couple of shoes are just any two random shoes that do not necessarily go together (but it can be the two shoes that came in a pair too). "A couple" is essentially just another phrase for the number "two". A couple of shoes means two shoes. Edit: "A couple" is also two people that are dating. Context should tell you to which it is refering. Examples: I saw a couple on the beach. = You saw two people, that are dating, on the beach. Have you seen any shoes? Yeah, I saw a couple on the beach. = You saw two shoes on the beach.

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I agree with @Nanren888: 'a couple of shoes' is not a normal expression. We don't say 'a couple of shoes'. The only time you might come across this is if they were probably two objects which did not belong together. For example: "The foxes in our neighbourhood are always leaving random objects around. Just look at what's in the garden this morning: there's half a Barbie doll, an empty tortilla chips packet, a chewed-up wallet and a couple of shoes". In this context, we know that these are likely to be two random shoes - maybe a child's sandal and a man's trainer. Two shoes of the same pair would only be called 'a couple' (meaning two) if it really didn't matter that they were a pair. Maybe all the family's shoes are stacked up on a shoe rack, and you grab two shoes without looking to throw at someone in a fight. These might be a pair or they might not be a pair - the point is that that these are two random shoes picked up by chance. However, if the key point is that the shoes are the left and right of the same pair, a native English speaker would never say 'a couple'. We would never say, for example, that someone is wearing a couple of new shoes. Two shoes, a left and a right, which are manufactured, bought and worn together, are always referred to as 'a pair of shoes'. I hope that's clear now.

Couple and pair means two in general counting and pair means two of the same kind while couple depends on the sentence that you will give emphasis like objects, weeks or days, however in this case you are talking about COUPLE OF SHOES it means exactly two shoes that match. One for your left foot and one for your right. PAIRS OF SHOES/COUPLES OF SHOES would refer to more than one pair (a left and right) for each pair.

Main difference. 'couple of shoes' - never heard this 'a pair of shoes' - the normal expression. . The first one might be used for some other sort of "shoe" that is not in paris. NOt very common, a thing to have. . After moving house, when we unpacked, I was a couple of shoes down. Never did find them. Had to throw their pairs away.