The spelling of "Wallker" can be explained using the International Phonetic Alphabet (IPA). The initial sound is a voiced bilabial stop, represented as /w/. This is followed by a centralized vowel sound represented as /ə/. The final sound is a voiceless velar stop represented as /k/. Therefore, the correct IPA transcription for "Wallker" would be /wɔːlkər/. It is important to note that the correct spelling of this word is actually "Walker" with two L's. Spelling mistakes are common, but using IPA helps to understand and correct them.