The word "CDCAL" is a tricky one to spell, as it contains a combination of sounds not often seen together in English. The IPA phonetic transcription reveals that the first sound is a "k" sound, represented by the symbol /k/. The following sound is a voiced dental fricative, written as /ð/. Finally, the word ends with a voiceless alveolar fricative, indicated by /s/. Putting it all together, the correct spelling of this word is C-D-ð-A-L, with the ð representing the unique dental sound in the middle.