Change SharePoint, Newsfeed, Skydrive and Sites text in SharePoint 2013 Team site

Hi folks,

here I am trying to change SharePoint 2013 team site look and feel. Trying to change SharePoint, Newsfeed, SkyDrive
and Sites text and links behind. Want to apply the same for the entire site collection.
Please suggest me here, how can I proceed.

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Cheers, R.