【Dip】 , 【immerse】 , 【submerge】 , 【duck】 , 【souse】 , 【dunk】  are comparable when meaning to plunge a person or thing into or as if into liquid.

【Dip】 implies a momentary or partial plunging into a liquid or a slight or cursory entrance into a subject.

【Immerse】 implies that the person or thing is covered by the liquid or buried or engrossed in something.

【Submerge】  implies complete and often prolonged immersion (as in an inundation) or a being overwhelmed or, sometimes, overpowered and made helpless.

It may suggest a sinking to the lowest state, grade, or status.

【Duck】 implies a sudden plunging and an almost immediate withdrawal.

【Souse】 adds to 【duck】 the suggestion of more prolonged immersion and often of a thorough soaking.

【Souse】 sometimes implies steeping of meat, fish, or other food in a pickle or tart liquid for the sake of preserving and flavoring it. It may often imply not only immersion but a being saturated and, hence, after liquor drinking a becoming intoxicated.

【Dunk】  in its basic use means to 【dip】 and soak something (as bread or a doughnut) in coffee, tea, or milk before eating it, but in many contexts it is equivalent to 【duck】 or 【immerse】 .