The spelling of the word "halladay" is based on the English system of phonetic spelling. The word "halladay" is pronounced as /hælədeɪ/ in IPA phonetic transcription. The first part of the word "hall" is pronounced with the short "a" sound and the second syllable "aday" is pronounced with the long "a" sound. The two "l" sounds are pronounced like a single consonant sound. By using the correct spelling and pronunciation, we can ensure clear communication and avoid any confusion.