'Hanged' versus 'Hung.' Is 'pair' singular or plural? Fossilized phrases.

1030. This week, we look at why "hang" has two past-tense forms: "hanged" and "hung." (And why I keep messing them up!) Then we expand on why "pair" can be singular or plural. And finally we look at why we hear some words only in set phrases such as "bated breath," "throes of agony," and "to and fro."