The spelling of the phrase "bank beaver" can be explained using IPA phonetic transcription. "Bank" is spelled /bæŋk/ using the phonetic symbols for the consonant sound "b" and the vowel sounds "æ" and "ŋ" for the nasal consonant sound. "Beaver" is spelled /ˈbiːvər/ using the symbols for the vowel sounds "iː" and "ə" and the consonant sounds "v" and "r". This phrase refers to a type of beaver that lives near riverbanks and builds dams to control water flow.