HELP! Indesign - Dynamic Spelling underlines every word in the document

[marivic_1559]

So I have this particular file that when I turn on the Dynamic Spelling to check Spelling errors, it underlines almost every word. I have checked the Preferences >Dictionary and it is already in english (See first screenshot below). When I check what is the spelling error under Check Spelling it doesn't seem to have any suggestions (refer to screenshot 2).  Other files that I open seem to be working fine, so I think it's just the way this document is setup. What should I check and do? 

I want to have a correct workflow of using Spell checker rather than turning the dynamic spelling off. I want to know how to fix this?

[Mike Witherell]

spell checking language is set up in your paragraph style. what is it set to?

[marivic_1559]

Is it this one? All of my paragraph styles are in English:USA 

[Dave Creamer of IDEAS]

Make sure a character styles is not overriding the English.

[Willi Adelberger]

If the Paragraph Styles have the correct language, no character sryle overrides with another language and no manual overrides use another language it is a bug I encountered several times too. 
what I do to get rid from this wrong marking are 2 methods wjich help me normally:

1. I apply a wrong language manually and then I select the text again and in the Paragraph Style Panel menu I select the command "Clear overrides". If this doesn't help, I go to the other method:
2. Save or export the dile as IDML (InDesign Markup Language), open that and save as neew INDD file. Now I have to check, if caused to the file inconsistency other properties have got unwanted changes. 

[leo.r]

Other files that I open seem to be working fine, so I think it's just the way this document is setup.

By @marivic_1559

Just to make sure: in your other files, is Dictionary also set to User Dictionary Only?