Spirits' Homecoming

Both films concern the topic of Korean comfort women in the second World War, although 'I Can Speak' also includes issues such as the treatment of the elderly in Korea.
The majority of the film time in 'Spirits' Homecoming' is set in the historical period and focuses primarily on the experiences of Korean comfort women in WW2. 'I Can Speak' on the other-hand is set in the present time and is therefore more concentrated on remembering and learning from the past events.
The genres of both films are also quite different. If you're up for something more lighthearted, 'I Can Speak' is the way to go. If not, just a warning...'Spirits' Homecoming' may be a little disturbing for some viewers as the raping scenes are quite violent and explicit (no full nudity shown however), and there are other violent scenes with killings and fighting.

You'll need a box of tissues for both of these films. They each portray characters dealing with death and coming to terms with their grief via traditional rituals. The Last Dance is more focussed on family dynamics whereas Spirits' Homecoming navigates a political taboo: Korean comfort women.

-WWII
-Comfort women

They're both about comfort women and the horrific ordeal they went through. Spirit's Homecoming, however, is much more graphic when describing and showing the abuse the young girls were subjected to.

Both these films tell stories about Japanese atrocities committed during WWII. While Dead to Rights is a typical war film, Spirits' Homecoming takes a more creative modern/historical approach to its narrative.