Full Idea
I once wrote that there are three linguistic devices that make it possible for us to frame undecidable statements: quantification over infinity totalities, as expressed by word such as 'never'; the subjunctive conditional form; and the past tense.
Gist of Idea
Undecidable statements result from quantifying over infinites, subjunctive conditionals, and the past tense
Source
Michael Dummett (Truth and the Past [2001], 4)
Book Reference
Dummett,Michael: 'Truth and the Past (Dewey Lectures)' [Columbia 2004], p.69
A Reaction
Dummett now repudiates the third one. Statements containing vague concepts also appear to be undecidable. Personally I have no problems with deciding (to a fair extent) about 'never x', and 'if x were true', and 'it was x'.