This thread is resolved. Here is a description of the problem and solution.
Problem: How do I activate English as one of my languages? the option is greyed out and cannot be selected in the Languages section.
Solution: You can hack the language settings to force the selection of English. Go to WPML -> Languages -> Add/Remove languages. Then, right click your screen and click "Inspect". On the English there will be a line that says something like "select=disabled". Just remove this from the console screen and you should then be able to check the box to add English.
This is the technical support forum for WPML - the multilingual WordPress plugin.