Final answer:
According to the poem, singing serves as a means of expressing emotions, finding solace, and fostering unity.
Step-by-step explanation:
The reasons for singing according to the poem "How Can I Keep from Singing?" can be seen as a form of expression of emotions, a way to find solace and relief, and a means of communication and unity. The poem suggests that singing is a way for slaves to convey their sorrows and find some comfort amidst their hardships. Additionally, it highlights how singing can be a powerful tool in bringing people together and inspiring them.