The spelling of the word "hn" may seem unusual, but it actually follows the principles of IPA phonetic transcription. The letters "h" and "n" represent two distinct sounds, with "h" being the voiceless glottal fricative and "n" being the voiced alveolar nasal. When these two sounds are combined, they form the phoneme /hn/. Therefore, the spelling of "hn" accurately represents the unique combination of these two sounds in IPA transcription.