I'll have a go at it. My answers are all based on a childhood and teenagehood of viewing and videotaping (on beta, no less!) I haven't actually seen the series in years, let alone on DVD, so I don't know the episode names at all.
1) Henry
2) Hawkeye (protesting the lack of variety in the mess hall)
3) Henry (to Hawkeye when his friend died during surgery)
4) Margaret (the episode in which Maragaret helped to care for a stay dog)
5) Hawkeye
6) Frank
7) Trapper
8) Hawkeye
9) BJ
10) Don't remember this one for the life of me, but I'll guess it's Father M.
11) Margaret (showing vulnerability in the Nurses' tent)
no subject
1) Henry
2) Hawkeye (protesting the lack of variety in the mess hall)
3) Henry (to Hawkeye when his friend died during surgery)
4) Margaret (the episode in which Maragaret helped to care for a stay dog)
5) Hawkeye
6) Frank
7) Trapper
8) Hawkeye
9) BJ
10) Don't remember this one for the life of me, but I'll guess it's Father M.
11) Margaret (showing vulnerability in the Nurses' tent)
12) Charles (on first arriving at the 4077th)
13) Radar
14) Trapper
15) ?
16) Klinger
17) Henry
18) Frank
19) Hawkeye
20) Charles