The form used by Emily Dickinson gives this poem a layer of sadness, ut also a distance from the feelings of the poem.
Explanation:
The poem ''We grow accustomed to the dark” is written by Emily Dickinson whose unusual style innovative use of phrases and punctuation are very much a part of her poetic language as much as her own words.
This poem too is no different as the hyphens here do not really connect the lines together as much as create and uncomfortable distance.
The poem says that the people who are accustomed to dark have also found themselves so dejected they are now almost at a distance from their feelings.
"His or her" would technically be the best fit, since it is acknowledging both genders, but it is very common to use "their" any most people wouldn't consider it wrong. <span />
