Music Themes: Writing, letters

If I Wrote You - Dar Williams
The Letter - Natalie Merchant

Themes - Music
Minor feel giving way to major resolutions at the end of phrases. - creates melancholy, insistent feel that does resolve phrase after phrase. 
Merchant's melody
fingerpicking -

Themes - Lyrics
Letter-writing to tell one's true feelings, rather than saying.
hopefullness, unrequited love, resignation, the need to express the feeling disregarding the reaction.
Fake idealized relationship ?