The dictionary used is determined by the language which has been set as a character attribute for the text.
Either the German language was applied manually to the text on the Character panel or Control panel, or the paragraph/character style is applying the German language attribute.
Bravo! It was in the character panel. Never knew that was there. Thank you Steve!
I made the change in the character panel and when I go to the spell check menu it reads English:USA. However, when I start the spellcheck it reverts to German. I deleted the paragraph and character styles and that did not fix either.
The language is a character level attribute, so you would have to select all of the text in the document and make the change.
This AppleScript (OSX only) will change every character and style in the active document.
set mylanguage to "German: 2006 Reform"
tell application "Adobe InDesign CC 2014"
set pstyles to all paragraph styles of active document
repeat with i from 1 to number of items in pstyles
set applied language of item i of pstyles to mylanguage
set cstyles to all character styles of active document
repeat with i from 1 to number of items in cstyles
set applied language of item i of cstyles to mylanguage
set applied language of every paragraph of every story of active document to mylanguage
Thanks Rob, I did end up cutting and pasting in a new doc and that seems to be a good work-around. Wouldn't be good for a mulit-page doc.
If pasting the text into a new document fixed it, then chances are the German language attribute was set in Basic Paragraph Style of your existing document. If you text was set to Basic Paragraph, or to a style based on Basic Paragraph, then pasting into the new document would take the attributes from the new document's Basic Paragraph presets.