This is the 9003rd most frequent Japanese word.
泳げ
"Swim" (imperative form).
Here, '泳ぐ' serves as the root form of '泳げ', used in the causative teaching context (to teach someone to swim). The word '泳げ' itself stems from '泳ぐ', which is conjugated differently here for grammatical correctness in context.
彼に泳ぐように教えました。
I taught him how to swim.
This sentence demonstrates the use of '泳げる' similarly to example one, focusing on the ability or opportunity to swim associated with enjoyment.
夏には川で泳げるのが楽しみです。
I look forward to the fact that I can swim in the river during summer.
In this sentence, '泳げ' is used to imply the possibility of swimming, expressed as '泳げる'. This usage indicates asking about the capability or permission for swimming in the sea.