From the sounds of it, the language has been set to United Kingdom during the installation process.
All that you'll need to do is open your settings and set the language to English (United States), then remove the former one.
This can be done either by using Cortana - search for 'region and language settings' - or from the quick action bar, all settings, time & language, region & language.
From there, click on 'add a language', select English, then English US, and that should install from Windows update. Following that, delete the previous.
Now, if the language is showing up as US English, it is possible to set the keyboard layout independently. Simply click on the language, then under keyboard add US QWERTY to the list; then -...