Walk: https://www.youtube.com/watch?v=gfkgn99Svfk

Talk: https://www.youtube.com/watch?v=BG9GBNr7kFk

Sock: https://www.youtube.com/watch?v=6cpffNd2GaA

Lock: https://www.youtube.com/watch?v=YPN_94VMk8Q

Sock and lock sound similar to me, and so do walk and talk. But walk/talk and sock/lock sound quite dissimilar.

Here in Canada all four rhyme, and are more similar to your sock/lock than your walk/talk.