I read both poems and I can immediately envision being in a beach. A white-sand beach filled with tropical fruit.
In "Dream Variations", I think of an undiscovered paradise where I am the only inhabitant. When darkness comes, it totally covers the beach and only the moon and stars provide the light.
In "The Tropics in New York", I envision a vacation spot where tropical fruits and fresh juices are being served.
For me, these places represent a simple and enjoyable time where stress is a stranger.
Mother tounge is basically just the language from your culture.
Explanation:
When somebody says something is in their "mother tounge" it means it is in their native language. For example, "The Sioux man recited a poem in his mother tounge, his face alight with passion."