If you mean 'speaker' as in not using a headset, but using your laptop's built-in speaker and mic... it's probably to be expected. Most laptops are pretty poorly designed and generate a lot of echo. Too much leaking from speaker to mic...
You're probably best to get a specialist speakerphone - I've used a Jabra one before that was really great : https://www.google.co.uk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=jabra%20speakerphone
Aaron
Aaron
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