LitCharts assigns a color and icon to each theme in The Hungry Tide, which you can use to track the themes throughout the work.
Language
Man vs. Nature
The Human Cost of Environmental Conservation
Idealism and Theory vs. Practicality and Action
Summary
Analysis
At night, Kanai is still in Nirmal's study when the generator goes out, and the room goes dark. He steps out onto the roof and admires the moonlit landscape. Some strange echo reaches Kanai, and dogs start to bark. Moyna appears in the doorway and asks if he heard "it"—the sound was a tiger, though Kanai recognizes he cannot say the word. He recognizes that Moyna looks anxious because Fokir is still out there with the tiger, so he assures her that he knows what to do. Angrily, she spits that Fokir is like a child and doesn't take any precautions.
Moyna sounds a lot like Nirmal here; Nirmal also appears to despise local wisdom that seeks to come to some sort of agreement with nature in favor of more modern (and way less religiously focused) pursuits, like education. The fact that Kanai cannot say the word "tiger" suggests that there's power in speaking the word—language can make things real, in essence.
Active
Themes
Kanai asks in a teasing tone if Moyna didn't know Fokir before they married. She says she did, but insists that Kanai wouldn't understand why she married him. This offends Kanai. He insists he'd certainly understand, given that he speaks six languages, but Moyna insists he's not a woman and doesn't know Fokir. Moyna leaves in a huff.
Kanai's insistence that he'd understand confirms that he believes fully in his own ability, as a man and a translator, to understand the world. However, he doesn't recognize that his experience and understanding of a situation isn't necessarily the same as everyone else's.